// SPDX-License-Identifier: GPL-2.0-or-later /* SCTP kernel implementation * (C) Copyright IBM Corp. 2001, 2004 * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2003 Intel Corp. * Copyright (c) 2001-2002 Nokia, Inc. * Copyright (c) 2001 La Monte H.P. Yarroll * * This file is part of the SCTP kernel implementation * * These functions interface with the sockets layer to implement the * SCTP Extensions for the Sockets API. * * Note that the descriptions from the specification are USER level * functions--this file is the functions which populate the struct proto * for SCTP which is the BOTTOM of the sockets interface. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <[email protected]> * * Written or modified by: * La Monte H.P. Yarroll <[email protected]> * Narasimha Budihal <[email protected]> * Karl Knutson <[email protected]> * Jon Grimm <[email protected]> * Xingang Guo <[email protected]> * Daisy Chang <[email protected]> * Sridhar Samudrala <[email protected]> * Inaky Perez-Gonzalez <[email protected]> * Ardelle Fan <[email protected]> * Ryan Layer <[email protected]> * Anup Pemmaiah <[email protected]> * Kevin Gao <[email protected]> */ #define pr_fmt(fmt) … #include <crypto/hash.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/wait.h> #include <linux/time.h> #include <linux/sched/signal.h> #include <linux/ip.h> #include <linux/capability.h> #include <linux/fcntl.h> #include <linux/poll.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/file.h> #include <linux/compat.h> #include <linux/rhashtable.h> #include <net/ip.h> #include <net/icmp.h> #include <net/route.h> #include <net/ipv6.h> #include <net/inet_common.h> #include <net/busy_poll.h> #include <trace/events/sock.h> #include <linux/socket.h> /* for sa_family_t */ #include <linux/export.h> #include <net/sock.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> #include <net/sctp/stream_sched.h> #include <net/rps.h> /* Forward declarations for internal helper functions. */ static bool sctp_writeable(const struct sock *sk); static void sctp_wfree(struct sk_buff *skb); static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p, size_t msg_len); static int sctp_wait_for_packet(struct sock *sk, int *err, long *timeo_p); static int sctp_wait_for_connect(struct sctp_association *, long *timeo_p); static int sctp_wait_for_accept(struct sock *sk, long timeo); static void sctp_wait_for_close(struct sock *sk, long timeo); static void sctp_destruct_sock(struct sock *sk); static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt, union sctp_addr *addr, int len); static int sctp_bindx_add(struct sock *, struct sockaddr *, int); static int sctp_bindx_rem(struct sock *, struct sockaddr *, int); static int sctp_send_asconf_add_ip(struct sock *, struct sockaddr *, int); static int sctp_send_asconf_del_ip(struct sock *, struct sockaddr *, int); static int sctp_send_asconf(struct sctp_association *asoc, struct sctp_chunk *chunk); static int sctp_do_bind(struct sock *, union sctp_addr *, int); static int sctp_autobind(struct sock *sk); static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, struct sctp_association *assoc, enum sctp_socket_type type); static unsigned long sctp_memory_pressure; static atomic_long_t sctp_memory_allocated; static DEFINE_PER_CPU(int, sctp_memory_per_cpu_fw_alloc); struct percpu_counter sctp_sockets_allocated; static void sctp_enter_memory_pressure(struct sock *sk) { … } /* Get the sndbuf space available at the time on the association. */ static inline int sctp_wspace(struct sctp_association *asoc) { … } /* Increment the used sndbuf space count of the corresponding association by * the size of the outgoing data chunk. * Also, set the skb destructor for sndbuf accounting later. * * Since it is always 1-1 between chunk and skb, and also a new skb is always * allocated for chunk bundling in sctp_packet_transmit(), we can use the * destructor in the data chunk skb for the purpose of the sndbuf space * tracking. */ static inline void sctp_set_owner_w(struct sctp_chunk *chunk) { … } static void sctp_clear_owner_w(struct sctp_chunk *chunk) { … } #define traverse_and_process() … static void sctp_for_each_tx_datachunk(struct sctp_association *asoc, bool clear, void (*cb)(struct sctp_chunk *)) { … } static void sctp_for_each_rx_skb(struct sctp_association *asoc, struct sock *sk, void (*cb)(struct sk_buff *, struct sock *)) { … } /* Verify that this is a valid address. */ static inline int sctp_verify_addr(struct sock *sk, union sctp_addr *addr, int len) { … } /* Look up the association by its id. If this is not a UDP-style * socket, the ID field is always ignored. */ struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id) { … } /* Look up the transport from an address and an assoc id. If both address and * id are specified, the associations matching the address and the id should be * the same. */ static struct sctp_transport *sctp_addr_id2transport(struct sock *sk, struct sockaddr_storage *addr, sctp_assoc_t id) { … } /* API 3.1.2 bind() - UDP Style Syntax * The syntax of bind() is, * * ret = bind(int sd, struct sockaddr *addr, int addrlen); * * sd - the socket descriptor returned by socket(). * addr - the address structure (struct sockaddr_in or struct * sockaddr_in6 [RFC 2553]), * addr_len - the size of the address structure. */ static int sctp_bind(struct sock *sk, struct sockaddr *addr, int addr_len) { … } static int sctp_get_port_local(struct sock *, union sctp_addr *); /* Verify this is a valid sockaddr. */ static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt, union sctp_addr *addr, int len) { … } static void sctp_auto_asconf_init(struct sctp_sock *sp) { … } /* Bind a local address either to an endpoint or to an association. */ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len) { … } /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks * * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged * at any one time. If a sender, after sending an ASCONF chunk, decides * it needs to transfer another ASCONF Chunk, it MUST wait until the * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a * subsequent ASCONF. Note this restriction binds each side, so at any * time two ASCONF may be in-transit on any given association (one sent * from each endpoint). */ static int sctp_send_asconf(struct sctp_association *asoc, struct sctp_chunk *chunk) { … } /* Add a list of addresses as bind addresses to local endpoint or * association. * * Basically run through each address specified in the addrs/addrcnt * array/length pair, determine if it is IPv6 or IPv4 and call * sctp_do_bind() on it. * * If any of them fails, then the operation will be reversed and the * ones that were added will be removed. * * Only sctp_setsockopt_bindx() is supposed to call this function. */ static int sctp_bindx_add(struct sock *sk, struct sockaddr *addrs, int addrcnt) { … } /* Send an ASCONF chunk with Add IP address parameters to all the peers of the * associations that are part of the endpoint indicating that a list of local * addresses are added to the endpoint. * * If any of the addresses is already in the bind address list of the * association, we do not send the chunk for that association. But it will not * affect other associations. * * Only sctp_setsockopt_bindx() is supposed to call this function. */ static int sctp_send_asconf_add_ip(struct sock *sk, struct sockaddr *addrs, int addrcnt) { … } /* Remove a list of addresses from bind addresses list. Do not remove the * last address. * * Basically run through each address specified in the addrs/addrcnt * array/length pair, determine if it is IPv6 or IPv4 and call * sctp_del_bind() on it. * * If any of them fails, then the operation will be reversed and the * ones that were removed will be added back. * * At least one address has to be left; if only one address is * available, the operation will return -EBUSY. * * Only sctp_setsockopt_bindx() is supposed to call this function. */ static int sctp_bindx_rem(struct sock *sk, struct sockaddr *addrs, int addrcnt) { … } /* Send an ASCONF chunk with Delete IP address parameters to all the peers of * the associations that are part of the endpoint indicating that a list of * local addresses are removed from the endpoint. * * If any of the addresses is already in the bind address list of the * association, we do not send the chunk for that association. But it will not * affect other associations. * * Only sctp_setsockopt_bindx() is supposed to call this function. */ static int sctp_send_asconf_del_ip(struct sock *sk, struct sockaddr *addrs, int addrcnt) { … } /* set addr events to assocs in the endpoint. ep and addr_wq must be locked */ int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw) { … } /* Helper for tunneling sctp_bindx() requests through sctp_setsockopt() * * API 8.1 * int sctp_bindx(int sd, struct sockaddr *addrs, int addrcnt, * int flags); * * If sd is an IPv4 socket, the addresses passed must be IPv4 addresses. * If the sd is an IPv6 socket, the addresses passed can either be IPv4 * or IPv6 addresses. * * A single address may be specified as INADDR_ANY or IN6ADDR_ANY, see * Section 3.1.2 for this usage. * * addrs is a pointer to an array of one or more socket addresses. Each * address is contained in its appropriate structure (i.e. struct * sockaddr_in or struct sockaddr_in6) the family of the address type * must be used to distinguish the address length (note that this * representation is termed a "packed array" of addresses). The caller * specifies the number of addresses in the array with addrcnt. * * On success, sctp_bindx() returns 0. On failure, sctp_bindx() returns * -1, and sets errno to the appropriate error code. * * For SCTP, the port given in each socket address must be the same, or * sctp_bindx() will fail, setting errno to EINVAL. * * The flags parameter is formed from the bitwise OR of zero or more of * the following currently defined flags: * * SCTP_BINDX_ADD_ADDR * * SCTP_BINDX_REM_ADDR * * SCTP_BINDX_ADD_ADDR directs SCTP to add the given addresses to the * association, and SCTP_BINDX_REM_ADDR directs SCTP to remove the given * addresses from the association. The two flags are mutually exclusive; * if both are given, sctp_bindx() will fail with EINVAL. A caller may * not remove all addresses from an association; sctp_bindx() will * reject such an attempt with EINVAL. * * An application can use sctp_bindx(SCTP_BINDX_ADD_ADDR) to associate * additional addresses with an endpoint after calling bind(). Or use * sctp_bindx(SCTP_BINDX_REM_ADDR) to remove some addresses a listening * socket is associated with so that no new association accepted will be * associated with those addresses. If the endpoint supports dynamic * address a SCTP_BINDX_REM_ADDR or SCTP_BINDX_ADD_ADDR may cause a * endpoint to send the appropriate message to the peer to change the * peers address lists. * * Adding and removing addresses from a connected association is * optional functionality. Implementations that do not support this * functionality should return EOPNOTSUPP. * * Basically do nothing but copying the addresses from user to kernel * land and invoking either sctp_bindx_add() or sctp_bindx_rem() on the sk. * This is used for tunneling the sctp_bindx() request through sctp_setsockopt() * from userspace. * * On exit there is no need to do sockfd_put(), sys_setsockopt() does * it. * * sk The sk of the socket * addrs The pointer to the addresses * addrssize Size of the addrs buffer * op Operation to perform (add or remove, see the flags of * sctp_bindx) * * Returns 0 if ok, <0 errno code on error. */ static int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *addrs, int addrs_size, int op) { … } static int sctp_bind_add(struct sock *sk, struct sockaddr *addrs, int addrlen) { … } static int sctp_connect_new_asoc(struct sctp_endpoint *ep, const union sctp_addr *daddr, const struct sctp_initmsg *init, struct sctp_transport **tp) { … } static int sctp_connect_add_peer(struct sctp_association *asoc, union sctp_addr *daddr, int addr_len) { … } /* __sctp_connect(struct sock* sk, struct sockaddr *kaddrs, int addrs_size) * * Common routine for handling connect() and sctp_connectx(). * Connect will come in with just a single address. */ static int __sctp_connect(struct sock *sk, struct sockaddr *kaddrs, int addrs_size, int flags, sctp_assoc_t *assoc_id) { … } /* Helper for tunneling sctp_connectx() requests through sctp_setsockopt() * * API 8.9 * int sctp_connectx(int sd, struct sockaddr *addrs, int addrcnt, * sctp_assoc_t *asoc); * * If sd is an IPv4 socket, the addresses passed must be IPv4 addresses. * If the sd is an IPv6 socket, the addresses passed can either be IPv4 * or IPv6 addresses. * * A single address may be specified as INADDR_ANY or IN6ADDR_ANY, see * Section 3.1.2 for this usage. * * addrs is a pointer to an array of one or more socket addresses. Each * address is contained in its appropriate structure (i.e. struct * sockaddr_in or struct sockaddr_in6) the family of the address type * must be used to distengish the address length (note that this * representation is termed a "packed array" of addresses). The caller * specifies the number of addresses in the array with addrcnt. * * On success, sctp_connectx() returns 0. It also sets the assoc_id to * the association id of the new association. On failure, sctp_connectx() * returns -1, and sets errno to the appropriate error code. The assoc_id * is not touched by the kernel. * * For SCTP, the port given in each socket address must be the same, or * sctp_connectx() will fail, setting errno to EINVAL. * * An application can use sctp_connectx to initiate an association with * an endpoint that is multi-homed. Much like sctp_bindx() this call * allows a caller to specify multiple addresses at which a peer can be * reached. The way the SCTP stack uses the list of addresses to set up * the association is implementation dependent. This function only * specifies that the stack will try to make use of all the addresses in * the list when needed. * * Note that the list of addresses passed in is only used for setting up * the association. It does not necessarily equal the set of addresses * the peer uses for the resulting association. If the caller wants to * find out the set of peer addresses, it must use sctp_getpaddrs() to * retrieve them after the association has been set up. * * Basically do nothing but copying the addresses from user to kernel * land and invoking either sctp_connectx(). This is used for tunneling * the sctp_connectx() request through sctp_setsockopt() from userspace. * * On exit there is no need to do sockfd_put(), sys_setsockopt() does * it. * * sk The sk of the socket * addrs The pointer to the addresses * addrssize Size of the addrs buffer * * Returns >=0 if ok, <0 errno code on error. */ static int __sctp_setsockopt_connectx(struct sock *sk, struct sockaddr *kaddrs, int addrs_size, sctp_assoc_t *assoc_id) { … } /* * This is an older interface. It's kept for backward compatibility * to the option that doesn't provide association id. */ static int sctp_setsockopt_connectx_old(struct sock *sk, struct sockaddr *kaddrs, int addrs_size) { … } /* * New interface for the API. The since the API is done with a socket * option, to make it simple we feed back the association id is as a return * indication to the call. Error is always negative and association id is * always positive. */ static int sctp_setsockopt_connectx(struct sock *sk, struct sockaddr *kaddrs, int addrs_size) { … } /* * New (hopefully final) interface for the API. * We use the sctp_getaddrs_old structure so that use-space library * can avoid any unnecessary allocations. The only different part * is that we store the actual length of the address buffer into the * addrs_num structure member. That way we can re-use the existing * code. */ #ifdef CONFIG_COMPAT struct compat_sctp_getaddrs_old { … }; #endif static int sctp_getsockopt_connectx3(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* API 3.1.4 close() - UDP Style Syntax * Applications use close() to perform graceful shutdown (as described in * Section 10.1 of [SCTP]) on ALL the associations currently represented * by a UDP-style socket. * * The syntax is * * ret = close(int sd); * * sd - the socket descriptor of the associations to be closed. * * To gracefully shutdown a specific association represented by the * UDP-style socket, an application should use the sendmsg() call, * passing no user data, but including the appropriate flag in the * ancillary data (see Section xxxx). * * If sd in the close() call is a branched-off socket representing only * one association, the shutdown is performed on that association only. * * 4.1.6 close() - TCP Style Syntax * * Applications use close() to gracefully close down an association. * * The syntax is: * * int close(int sd); * * sd - the socket descriptor of the association to be closed. * * After an application calls close() on a socket descriptor, no further * socket operations will succeed on that descriptor. * * API 7.1.4 SO_LINGER * * An application using the TCP-style socket can use this option to * perform the SCTP ABORT primitive. The linger option structure is: * * struct linger { * int l_onoff; // option on/off * int l_linger; // linger time * }; * * To enable the option, set l_onoff to 1. If the l_linger value is set * to 0, calling close() is the same as the ABORT primitive. If the * value is set to a negative value, the setsockopt() call will return * an error. If the value is set to a positive value linger_time, the * close() can be blocked for at most linger_time ms. If the graceful * shutdown phase does not finish during this period, close() will * return but the graceful shutdown phase continues in the system. */ static void sctp_close(struct sock *sk, long timeout) { … } /* Handle EPIPE error. */ static int sctp_error(struct sock *sk, int flags, int err) { … } /* API 3.1.3 sendmsg() - UDP Style Syntax * * An application uses sendmsg() and recvmsg() calls to transmit data to * and receive data from its peer. * * ssize_t sendmsg(int socket, const struct msghdr *message, * int flags); * * socket - the socket descriptor of the endpoint. * message - pointer to the msghdr structure which contains a single * user message and possibly some ancillary data. * * See Section 5 for complete description of the data * structures. * * flags - flags sent or received with the user message, see Section * 5 for complete description of the flags. * * Note: This function could use a rewrite especially when explicit * connect support comes in. */ /* BUG: We do not implement the equivalent of sk_stream_wait_memory(). */ static int sctp_msghdr_parse(const struct msghdr *msg, struct sctp_cmsgs *cmsgs); static int sctp_sendmsg_parse(struct sock *sk, struct sctp_cmsgs *cmsgs, struct sctp_sndrcvinfo *srinfo, const struct msghdr *msg, size_t msg_len) { … } static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags, struct sctp_cmsgs *cmsgs, union sctp_addr *daddr, struct sctp_transport **tp) { … } static int sctp_sendmsg_check_sflags(struct sctp_association *asoc, __u16 sflags, struct msghdr *msg, size_t msg_len) { … } static int sctp_sendmsg_to_asoc(struct sctp_association *asoc, struct msghdr *msg, size_t msg_len, struct sctp_transport *transport, struct sctp_sndrcvinfo *sinfo) { … } static union sctp_addr *sctp_sendmsg_get_daddr(struct sock *sk, const struct msghdr *msg, struct sctp_cmsgs *cmsgs) { … } static void sctp_sendmsg_update_sinfo(struct sctp_association *asoc, struct sctp_sndrcvinfo *sinfo, struct sctp_cmsgs *cmsgs) { … } static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len) { … } /* This is an extended version of skb_pull() that removes the data from the * start of a skb even when data is spread across the list of skb's in the * frag_list. len specifies the total amount of data that needs to be removed. * when 'len' bytes could be removed from the skb, it returns 0. * If 'len' exceeds the total skb length, it returns the no. of bytes that * could not be removed. */ static int sctp_skb_pull(struct sk_buff *skb, int len) { … } /* API 3.1.3 recvmsg() - UDP Style Syntax * * ssize_t recvmsg(int socket, struct msghdr *message, * int flags); * * socket - the socket descriptor of the endpoint. * message - pointer to the msghdr structure which contains a single * user message and possibly some ancillary data. * * See Section 5 for complete description of the data * structures. * * flags - flags sent or received with the user message, see Section * 5 for complete description of the flags. */ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags, int *addr_len) { … } /* 7.1.12 Enable/Disable message fragmentation (SCTP_DISABLE_FRAGMENTS) * * This option is a on/off flag. If enabled no SCTP message * fragmentation will be performed. Instead if a message being sent * exceeds the current PMTU size, the message will NOT be sent and * instead a error will be indicated to the user. */ static int sctp_setsockopt_disable_fragments(struct sock *sk, int *val, unsigned int optlen) { … } static int sctp_setsockopt_events(struct sock *sk, __u8 *sn_type, unsigned int optlen) { … } /* 7.1.8 Automatic Close of associations (SCTP_AUTOCLOSE) * * This socket option is applicable to the UDP-style socket only. When * set it will cause associations that are idle for more than the * specified number of seconds to automatically close. An association * being idle is defined an association that has NOT sent or received * user data. The special value of '0' indicates that no automatic * close of any associations should be performed. The option expects an * integer defining the number of seconds of idle time before an * association is closed. */ static int sctp_setsockopt_autoclose(struct sock *sk, u32 *optval, unsigned int optlen) { … } /* 7.1.13 Peer Address Parameters (SCTP_PEER_ADDR_PARAMS) * * Applications can enable or disable heartbeats for any peer address of * an association, modify an address's heartbeat interval, force a * heartbeat to be sent immediately, and adjust the address's maximum * number of retransmissions sent before an address is considered * unreachable. The following structure is used to access and modify an * address's parameters: * * struct sctp_paddrparams { * sctp_assoc_t spp_assoc_id; * struct sockaddr_storage spp_address; * uint32_t spp_hbinterval; * uint16_t spp_pathmaxrxt; * uint32_t spp_pathmtu; * uint32_t spp_sackdelay; * uint32_t spp_flags; * uint32_t spp_ipv6_flowlabel; * uint8_t spp_dscp; * }; * * spp_assoc_id - (one-to-many style socket) This is filled in the * application, and identifies the association for * this query. * spp_address - This specifies which address is of interest. * spp_hbinterval - This contains the value of the heartbeat interval, * in milliseconds. If a value of zero * is present in this field then no changes are to * be made to this parameter. * spp_pathmaxrxt - This contains the maximum number of * retransmissions before this address shall be * considered unreachable. If a value of zero * is present in this field then no changes are to * be made to this parameter. * spp_pathmtu - When Path MTU discovery is disabled the value * specified here will be the "fixed" path mtu. * Note that if the spp_address field is empty * then all associations on this address will * have this fixed path mtu set upon them. * * spp_sackdelay - When delayed sack is enabled, this value specifies * the number of milliseconds that sacks will be delayed * for. This value will apply to all addresses of an * association if the spp_address field is empty. Note * also, that if delayed sack is enabled and this * value is set to 0, no change is made to the last * recorded delayed sack timer value. * * spp_flags - These flags are used to control various features * on an association. The flag field may contain * zero or more of the following options. * * SPP_HB_ENABLE - Enable heartbeats on the * specified address. Note that if the address * field is empty all addresses for the association * have heartbeats enabled upon them. * * SPP_HB_DISABLE - Disable heartbeats on the * speicifed address. Note that if the address * field is empty all addresses for the association * will have their heartbeats disabled. Note also * that SPP_HB_ENABLE and SPP_HB_DISABLE are * mutually exclusive, only one of these two should * be specified. Enabling both fields will have * undetermined results. * * SPP_HB_DEMAND - Request a user initiated heartbeat * to be made immediately. * * SPP_HB_TIME_IS_ZERO - Specify's that the time for * heartbeat delayis to be set to the value of 0 * milliseconds. * * SPP_PMTUD_ENABLE - This field will enable PMTU * discovery upon the specified address. Note that * if the address feild is empty then all addresses * on the association are effected. * * SPP_PMTUD_DISABLE - This field will disable PMTU * discovery upon the specified address. Note that * if the address feild is empty then all addresses * on the association are effected. Not also that * SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE are mutually * exclusive. Enabling both will have undetermined * results. * * SPP_SACKDELAY_ENABLE - Setting this flag turns * on delayed sack. The time specified in spp_sackdelay * is used to specify the sack delay for this address. Note * that if spp_address is empty then all addresses will * enable delayed sack and take on the sack delay * value specified in spp_sackdelay. * SPP_SACKDELAY_DISABLE - Setting this flag turns * off delayed sack. If the spp_address field is blank then * delayed sack is disabled for the entire association. Note * also that this field is mutually exclusive to * SPP_SACKDELAY_ENABLE, setting both will have undefined * results. * * SPP_IPV6_FLOWLABEL: Setting this flag enables the * setting of the IPV6 flow label value. The value is * contained in the spp_ipv6_flowlabel field. * Upon retrieval, this flag will be set to indicate that * the spp_ipv6_flowlabel field has a valid value returned. * If a specific destination address is set (in the * spp_address field), then the value returned is that of * the address. If just an association is specified (and * no address), then the association's default flow label * is returned. If neither an association nor a destination * is specified, then the socket's default flow label is * returned. For non-IPv6 sockets, this flag will be left * cleared. * * SPP_DSCP: Setting this flag enables the setting of the * Differentiated Services Code Point (DSCP) value * associated with either the association or a specific * address. The value is obtained in the spp_dscp field. * Upon retrieval, this flag will be set to indicate that * the spp_dscp field has a valid value returned. If a * specific destination address is set when called (in the * spp_address field), then that specific destination * address's DSCP value is returned. If just an association * is specified, then the association's default DSCP is * returned. If neither an association nor a destination is * specified, then the socket's default DSCP is returned. * * spp_ipv6_flowlabel * - This field is used in conjunction with the * SPP_IPV6_FLOWLABEL flag and contains the IPv6 flow label. * The 20 least significant bits are used for the flow * label. This setting has precedence over any IPv6-layer * setting. * * spp_dscp - This field is used in conjunction with the SPP_DSCP flag * and contains the DSCP. The 6 most significant bits are * used for the DSCP. This setting has precedence over any * IPv4- or IPv6- layer setting. */ static int sctp_apply_peer_addr_params(struct sctp_paddrparams *params, struct sctp_transport *trans, struct sctp_association *asoc, struct sctp_sock *sp, int hb_change, int pmtud_change, int sackdelay_change) { … } static int sctp_setsockopt_peer_addr_params(struct sock *sk, struct sctp_paddrparams *params, unsigned int optlen) { … } static inline __u32 sctp_spp_sackdelay_enable(__u32 param_flags) { … } static inline __u32 sctp_spp_sackdelay_disable(__u32 param_flags) { … } static void sctp_apply_asoc_delayed_ack(struct sctp_sack_info *params, struct sctp_association *asoc) { … } /* * 7.1.23. Get or set delayed ack timer (SCTP_DELAYED_SACK) * * This option will effect the way delayed acks are performed. This * option allows you to get or set the delayed ack time, in * milliseconds. It also allows changing the delayed ack frequency. * Changing the frequency to 1 disables the delayed sack algorithm. If * the assoc_id is 0, then this sets or gets the endpoints default * values. If the assoc_id field is non-zero, then the set or get * effects the specified association for the one to many model (the * assoc_id field is ignored by the one to one model). Note that if * sack_delay or sack_freq are 0 when setting this option, then the * current values will remain unchanged. * * struct sctp_sack_info { * sctp_assoc_t sack_assoc_id; * uint32_t sack_delay; * uint32_t sack_freq; * }; * * sack_assoc_id - This parameter, indicates which association the user * is performing an action upon. Note that if this field's value is * zero then the endpoints default value is changed (effecting future * associations only). * * sack_delay - This parameter contains the number of milliseconds that * the user is requesting the delayed ACK timer be set to. Note that * this value is defined in the standard to be between 200 and 500 * milliseconds. * * sack_freq - This parameter contains the number of packets that must * be received before a sack is sent without waiting for the delay * timer to expire. The default value for this is 2, setting this * value to 1 will disable the delayed sack algorithm. */ static int __sctp_setsockopt_delayed_ack(struct sock *sk, struct sctp_sack_info *params) { … } static int sctp_setsockopt_delayed_ack(struct sock *sk, struct sctp_sack_info *params, unsigned int optlen) { … } /* 7.1.3 Initialization Parameters (SCTP_INITMSG) * * Applications can specify protocol parameters for the default association * initialization. The option name argument to setsockopt() and getsockopt() * is SCTP_INITMSG. * * Setting initialization parameters is effective only on an unconnected * socket (for UDP-style sockets only future associations are effected * by the change). With TCP-style sockets, this option is inherited by * sockets derived from a listener socket. */ static int sctp_setsockopt_initmsg(struct sock *sk, struct sctp_initmsg *sinit, unsigned int optlen) { … } /* * 7.1.14 Set default send parameters (SCTP_DEFAULT_SEND_PARAM) * * Applications that wish to use the sendto() system call may wish to * specify a default set of parameters that would normally be supplied * through the inclusion of ancillary data. This socket option allows * such an application to set the default sctp_sndrcvinfo structure. * The application that wishes to use this socket option simply passes * in to this call the sctp_sndrcvinfo structure defined in Section * 5.2.2) The input parameters accepted by this call include * sinfo_stream, sinfo_flags, sinfo_ppid, sinfo_context, * sinfo_timetolive. The user must provide the sinfo_assoc_id field in * to this call if the caller is using the UDP model. */ static int sctp_setsockopt_default_send_param(struct sock *sk, struct sctp_sndrcvinfo *info, unsigned int optlen) { … } /* RFC6458, Section 8.1.31. Set/get Default Send Parameters * (SCTP_DEFAULT_SNDINFO) */ static int sctp_setsockopt_default_sndinfo(struct sock *sk, struct sctp_sndinfo *info, unsigned int optlen) { … } /* 7.1.10 Set Primary Address (SCTP_PRIMARY_ADDR) * * Requests that the local SCTP stack use the enclosed peer address as * the association primary. The enclosed address must be one of the * association peer's addresses. */ static int sctp_setsockopt_primary_addr(struct sock *sk, struct sctp_prim *prim, unsigned int optlen) { … } /* * 7.1.5 SCTP_NODELAY * * Turn on/off any Nagle-like algorithm. This means that packets are * generally sent as soon as possible and no unnecessary delays are * introduced, at the cost of more packets in the network. Expects an * integer boolean flag. */ static int sctp_setsockopt_nodelay(struct sock *sk, int *val, unsigned int optlen) { … } /* * * 7.1.1 SCTP_RTOINFO * * The protocol parameters used to initialize and bound retransmission * timeout (RTO) are tunable. sctp_rtoinfo structure is used to access * and modify these parameters. * All parameters are time values, in milliseconds. A value of 0, when * modifying the parameters, indicates that the current value should not * be changed. * */ static int sctp_setsockopt_rtoinfo(struct sock *sk, struct sctp_rtoinfo *rtoinfo, unsigned int optlen) { … } /* * * 7.1.2 SCTP_ASSOCINFO * * This option is used to tune the maximum retransmission attempts * of the association. * Returns an error if the new association retransmission value is * greater than the sum of the retransmission value of the peer. * See [SCTP] for more information. * */ static int sctp_setsockopt_associnfo(struct sock *sk, struct sctp_assocparams *assocparams, unsigned int optlen) { … } /* * 7.1.16 Set/clear IPv4 mapped addresses (SCTP_I_WANT_MAPPED_V4_ADDR) * * This socket option is a boolean flag which turns on or off mapped V4 * addresses. If this option is turned on and the socket is type * PF_INET6, then IPv4 addresses will be mapped to V6 representation. * If this option is turned off, then no mapping will be done of V4 * addresses and a user will receive both PF_INET6 and PF_INET type * addresses on the socket. */ static int sctp_setsockopt_mappedv4(struct sock *sk, int *val, unsigned int optlen) { … } /* * 8.1.16. Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG) * This option will get or set the maximum size to put in any outgoing * SCTP DATA chunk. If a message is larger than this size it will be * fragmented by SCTP into the specified size. Note that the underlying * SCTP implementation may fragment into smaller sized chunks when the * PMTU of the underlying association is smaller than the value set by * the user. The default value for this option is '0' which indicates * the user is NOT limiting fragmentation and only the PMTU will effect * SCTP's choice of DATA chunk size. Note also that values set larger * than the maximum size of an IP datagram will effectively let SCTP * control fragmentation (i.e. the same as setting this option to 0). * * The following structure is used to access and modify this parameter: * * struct sctp_assoc_value { * sctp_assoc_t assoc_id; * uint32_t assoc_value; * }; * * assoc_id: This parameter is ignored for one-to-one style sockets. * For one-to-many style sockets this parameter indicates which * association the user is performing an action upon. Note that if * this field's value is zero then the endpoints default value is * changed (effecting future associations only). * assoc_value: This parameter specifies the maximum size in bytes. */ static int sctp_setsockopt_maxseg(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } /* * 7.1.9 Set Peer Primary Address (SCTP_SET_PEER_PRIMARY_ADDR) * * Requests that the peer mark the enclosed address as the association * primary. The enclosed address must be one of the association's * locally bound addresses. The following structure is used to make a * set primary request: */ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, struct sctp_setpeerprim *prim, unsigned int optlen) { … } static int sctp_setsockopt_adaptation_layer(struct sock *sk, struct sctp_setadaptation *adapt, unsigned int optlen) { … } /* * 7.1.29. Set or Get the default context (SCTP_CONTEXT) * * The context field in the sctp_sndrcvinfo structure is normally only * used when a failed message is retrieved holding the value that was * sent down on the actual send call. This option allows the setting of * a default context on an association basis that will be received on * reading messages from the peer. This is especially helpful in the * one-2-many model for an application to keep some reference to an * internal state machine that is processing messages on the * association. Note that the setting of this value only effects * received messages from the peer and does not effect the value that is * saved with outbound messages. */ static int sctp_setsockopt_context(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } /* * 7.1.24. Get or set fragmented interleave (SCTP_FRAGMENT_INTERLEAVE) * * This options will at a minimum specify if the implementation is doing * fragmented interleave. Fragmented interleave, for a one to many * socket, is when subsequent calls to receive a message may return * parts of messages from different associations. Some implementations * may allow you to turn this value on or off. If so, when turned off, * no fragment interleave will occur (which will cause a head of line * blocking amongst multiple associations sharing the same one to many * socket). When this option is turned on, then each receive call may * come from a different association (thus the user must receive data * with the extended calls (e.g. sctp_recvmsg) to keep track of which * association each receive belongs to. * * This option takes a boolean value. A non-zero value indicates that * fragmented interleave is on. A value of zero indicates that * fragmented interleave is off. * * Note that it is important that an implementation that allows this * option to be turned on, have it off by default. Otherwise an unaware * application using the one to many model may become confused and act * incorrectly. */ static int sctp_setsockopt_fragment_interleave(struct sock *sk, int *val, unsigned int optlen) { … } /* * 8.1.21. Set or Get the SCTP Partial Delivery Point * (SCTP_PARTIAL_DELIVERY_POINT) * * This option will set or get the SCTP partial delivery point. This * point is the size of a message where the partial delivery API will be * invoked to help free up rwnd space for the peer. Setting this to a * lower value will cause partial deliveries to happen more often. The * calls argument is an integer that sets or gets the partial delivery * point. Note also that the call will fail if the user attempts to set * this value larger than the socket receive buffer size. * * Note that any single message having a length smaller than or equal to * the SCTP partial delivery point will be delivered in one single read * call as long as the user provided buffer is large enough to hold the * message. */ static int sctp_setsockopt_partial_delivery_point(struct sock *sk, u32 *val, unsigned int optlen) { … } /* * 7.1.28. Set or Get the maximum burst (SCTP_MAX_BURST) * * This option will allow a user to change the maximum burst of packets * that can be emitted by this association. Note that the default value * is 4, and some implementations may restrict this setting so that it * can only be lowered. * * NOTE: This text doesn't seem right. Do this on a socket basis with * future associations inheriting the socket value. */ static int sctp_setsockopt_maxburst(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } /* * 7.1.18. Add a chunk that must be authenticated (SCTP_AUTH_CHUNK) * * This set option adds a chunk type that the user is requesting to be * received only in an authenticated way. Changes to the list of chunks * will only effect future associations on the socket. */ static int sctp_setsockopt_auth_chunk(struct sock *sk, struct sctp_authchunk *val, unsigned int optlen) { … } /* * 7.1.19. Get or set the list of supported HMAC Identifiers (SCTP_HMAC_IDENT) * * This option gets or sets the list of HMAC algorithms that the local * endpoint requires the peer to use. */ static int sctp_setsockopt_hmac_ident(struct sock *sk, struct sctp_hmacalgo *hmacs, unsigned int optlen) { … } /* * 7.1.20. Set a shared key (SCTP_AUTH_KEY) * * This option will set a shared secret key which is used to build an * association shared key. */ static int sctp_setsockopt_auth_key(struct sock *sk, struct sctp_authkey *authkey, unsigned int optlen) { … } /* * 7.1.21. Get or set the active shared key (SCTP_AUTH_ACTIVE_KEY) * * This option will get or set the active shared key to be used to build * the association shared key. */ static int sctp_setsockopt_active_key(struct sock *sk, struct sctp_authkeyid *val, unsigned int optlen) { … } /* * 7.1.22. Delete a shared key (SCTP_AUTH_DELETE_KEY) * * This set option will delete a shared secret key from use. */ static int sctp_setsockopt_del_key(struct sock *sk, struct sctp_authkeyid *val, unsigned int optlen) { … } /* * 8.3.4 Deactivate a Shared Key (SCTP_AUTH_DEACTIVATE_KEY) * * This set option will deactivate a shared secret key. */ static int sctp_setsockopt_deactivate_key(struct sock *sk, struct sctp_authkeyid *val, unsigned int optlen) { … } /* * 8.1.23 SCTP_AUTO_ASCONF * * This option will enable or disable the use of the automatic generation of * ASCONF chunks to add and delete addresses to an existing association. Note * that this option has two caveats namely: a) it only affects sockets that * are bound to all addresses available to the SCTP stack, and b) the system * administrator may have an overriding control that turns the ASCONF feature * off no matter what setting the socket option may have. * This option expects an integer boolean flag, where a non-zero value turns on * the option, and a zero value turns off the option. * Note. In this implementation, socket operation overrides default parameter * being set by sysctl as well as FreeBSD implementation */ static int sctp_setsockopt_auto_asconf(struct sock *sk, int *val, unsigned int optlen) { … } /* * SCTP_PEER_ADDR_THLDS * * This option allows us to alter the partially failed threshold for one or all * transports in an association. See Section 6.1 of: * http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt */ static int sctp_setsockopt_paddr_thresholds(struct sock *sk, struct sctp_paddrthlds_v2 *val, unsigned int optlen, bool v2) { … } static int sctp_setsockopt_recvrcvinfo(struct sock *sk, int *val, unsigned int optlen) { … } static int sctp_setsockopt_recvnxtinfo(struct sock *sk, int *val, unsigned int optlen) { … } static int sctp_setsockopt_pr_supported(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_default_prinfo(struct sock *sk, struct sctp_default_prinfo *info, unsigned int optlen) { … } static int sctp_setsockopt_reconfig_supported(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_enable_strreset(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_reset_streams(struct sock *sk, struct sctp_reset_streams *params, unsigned int optlen) { … } static int sctp_setsockopt_reset_assoc(struct sock *sk, sctp_assoc_t *associd, unsigned int optlen) { … } static int sctp_setsockopt_add_streams(struct sock *sk, struct sctp_add_streams *params, unsigned int optlen) { … } static int sctp_setsockopt_scheduler(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_scheduler_value(struct sock *sk, struct sctp_stream_value *params, unsigned int optlen) { … } static int sctp_setsockopt_interleaving_supported(struct sock *sk, struct sctp_assoc_value *p, unsigned int optlen) { … } static int sctp_setsockopt_reuse_port(struct sock *sk, int *val, unsigned int optlen) { … } static int sctp_assoc_ulpevent_type_set(struct sctp_event *param, struct sctp_association *asoc) { … } static int sctp_setsockopt_event(struct sock *sk, struct sctp_event *param, unsigned int optlen) { … } static int sctp_setsockopt_asconf_supported(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_auth_supported(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_ecn_supported(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_pf_expose(struct sock *sk, struct sctp_assoc_value *params, unsigned int optlen) { … } static int sctp_setsockopt_encap_port(struct sock *sk, struct sctp_udpencaps *encap, unsigned int optlen) { … } static int sctp_setsockopt_probe_interval(struct sock *sk, struct sctp_probeinterval *params, unsigned int optlen) { … } /* API 6.2 setsockopt(), getsockopt() * * Applications use setsockopt() and getsockopt() to set or retrieve * socket options. Socket options are used to change the default * behavior of sockets calls. They are described in Section 7. * * The syntax is: * * ret = getsockopt(int sd, int level, int optname, void __user *optval, * int __user *optlen); * ret = setsockopt(int sd, int level, int optname, const void __user *optval, * int optlen); * * sd - the socket descript. * level - set to IPPROTO_SCTP for all SCTP options. * optname - the option name. * optval - the buffer to store the value of the option. * optlen - the size of the buffer. */ static int sctp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, unsigned int optlen) { … } /* API 3.1.6 connect() - UDP Style Syntax * * An application may use the connect() call in the UDP model to initiate an * association without sending data. * * The syntax is: * * ret = connect(int sd, const struct sockaddr *nam, socklen_t len); * * sd: the socket descriptor to have a new association added to. * * nam: the address structure (either struct sockaddr_in or struct * sockaddr_in6 defined in RFC2553 [7]). * * len: the size of the address. */ static int sctp_connect(struct sock *sk, struct sockaddr *addr, int addr_len, int flags) { … } int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags) { … } /* Only called when shutdown a listening SCTP socket. */ static int sctp_disconnect(struct sock *sk, int flags) { … } /* 4.1.4 accept() - TCP Style Syntax * * Applications use accept() call to remove an established SCTP * association from the accept queue of the endpoint. A new socket * descriptor will be returned from accept() to represent the newly * formed association. */ static struct sock *sctp_accept(struct sock *sk, struct proto_accept_arg *arg) { … } /* The SCTP ioctl handler. */ static int sctp_ioctl(struct sock *sk, int cmd, int *karg) { … } /* This is the function which gets called during socket creation to * initialized the SCTP-specific portion of the sock. * The sock structure should already be zero-filled memory. */ static int sctp_init_sock(struct sock *sk) { … } /* Cleanup any SCTP per socket resources. Must be called with * sock_net(sk)->sctp.addr_wq_lock held if sp->do_auto_asconf is true */ static void sctp_destroy_sock(struct sock *sk) { … } /* Triggered when there are no references on the socket anymore */ static void sctp_destruct_common(struct sock *sk) { … } static void sctp_destruct_sock(struct sock *sk) { … } /* API 4.1.7 shutdown() - TCP Style Syntax * int shutdown(int socket, int how); * * sd - the socket descriptor of the association to be closed. * how - Specifies the type of shutdown. The values are * as follows: * SHUT_RD * Disables further receive operations. No SCTP * protocol action is taken. * SHUT_WR * Disables further send operations, and initiates * the SCTP shutdown sequence. * SHUT_RDWR * Disables further send and receive operations * and initiates the SCTP shutdown sequence. */ static void sctp_shutdown(struct sock *sk, int how) { … } int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc, struct sctp_info *info) { … } EXPORT_SYMBOL_GPL(…); /* use callback to avoid exporting the core structure */ void sctp_transport_walk_start(struct rhashtable_iter *iter) __acquires(RCU) { … } void sctp_transport_walk_stop(struct rhashtable_iter *iter) __releases(RCU) { … } struct sctp_transport *sctp_transport_get_next(struct net *net, struct rhashtable_iter *iter) { … } struct sctp_transport *sctp_transport_get_idx(struct net *net, struct rhashtable_iter *iter, int pos) { … } int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p) { … } EXPORT_SYMBOL_GPL(…); int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net, const union sctp_addr *laddr, const union sctp_addr *paddr, void *p, int dif) { … } EXPORT_SYMBOL_GPL(…); int sctp_transport_traverse_process(sctp_callback_t cb, sctp_callback_t cb_done, struct net *net, int *pos, void *p) { … } EXPORT_SYMBOL_GPL(…); /* 7.2.1 Association Status (SCTP_STATUS) * Applications can retrieve current status information about an * association, including association state, peer receiver window size, * number of unacked data chunks, and number of data chunks pending * receipt. This information is read-only. */ static int sctp_getsockopt_sctp_status(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.2.2 Peer Address Information (SCTP_GET_PEER_ADDR_INFO) * * Applications can retrieve information about a specific peer address * of an association, including its reachability state, congestion * window, and retransmission timer values. This information is * read-only. */ static int sctp_getsockopt_peer_addr_info(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.12 Enable/Disable message fragmentation (SCTP_DISABLE_FRAGMENTS) * * This option is a on/off flag. If enabled no SCTP message * fragmentation will be performed. Instead if a message being sent * exceeds the current PMTU size, the message will NOT be sent and * instead a error will be indicated to the user. */ static int sctp_getsockopt_disable_fragments(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.15 Set notification and ancillary events (SCTP_EVENTS) * * This socket option is used to specify various notifications and * ancillary data the user wishes to receive. */ static int sctp_getsockopt_events(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.8 Automatic Close of associations (SCTP_AUTOCLOSE) * * This socket option is applicable to the UDP-style socket only. When * set it will cause associations that are idle for more than the * specified number of seconds to automatically close. An association * being idle is defined an association that has NOT sent or received * user data. The special value of '0' indicates that no automatic * close of any associations should be performed. The option expects an * integer defining the number of seconds of idle time before an * association is closed. */ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* Helper routine to branch off an association to a new socket. */ int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp) { … } EXPORT_SYMBOL(…); static int sctp_getsockopt_peeloff_common(struct sock *sk, sctp_peeloff_arg_t *peeloff, struct file **newfile, unsigned flags) { … } static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_peeloff_flags(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.13 Peer Address Parameters (SCTP_PEER_ADDR_PARAMS) * * Applications can enable or disable heartbeats for any peer address of * an association, modify an address's heartbeat interval, force a * heartbeat to be sent immediately, and adjust the address's maximum * number of retransmissions sent before an address is considered * unreachable. The following structure is used to access and modify an * address's parameters: * * struct sctp_paddrparams { * sctp_assoc_t spp_assoc_id; * struct sockaddr_storage spp_address; * uint32_t spp_hbinterval; * uint16_t spp_pathmaxrxt; * uint32_t spp_pathmtu; * uint32_t spp_sackdelay; * uint32_t spp_flags; * }; * * spp_assoc_id - (one-to-many style socket) This is filled in the * application, and identifies the association for * this query. * spp_address - This specifies which address is of interest. * spp_hbinterval - This contains the value of the heartbeat interval, * in milliseconds. If a value of zero * is present in this field then no changes are to * be made to this parameter. * spp_pathmaxrxt - This contains the maximum number of * retransmissions before this address shall be * considered unreachable. If a value of zero * is present in this field then no changes are to * be made to this parameter. * spp_pathmtu - When Path MTU discovery is disabled the value * specified here will be the "fixed" path mtu. * Note that if the spp_address field is empty * then all associations on this address will * have this fixed path mtu set upon them. * * spp_sackdelay - When delayed sack is enabled, this value specifies * the number of milliseconds that sacks will be delayed * for. This value will apply to all addresses of an * association if the spp_address field is empty. Note * also, that if delayed sack is enabled and this * value is set to 0, no change is made to the last * recorded delayed sack timer value. * * spp_flags - These flags are used to control various features * on an association. The flag field may contain * zero or more of the following options. * * SPP_HB_ENABLE - Enable heartbeats on the * specified address. Note that if the address * field is empty all addresses for the association * have heartbeats enabled upon them. * * SPP_HB_DISABLE - Disable heartbeats on the * speicifed address. Note that if the address * field is empty all addresses for the association * will have their heartbeats disabled. Note also * that SPP_HB_ENABLE and SPP_HB_DISABLE are * mutually exclusive, only one of these two should * be specified. Enabling both fields will have * undetermined results. * * SPP_HB_DEMAND - Request a user initiated heartbeat * to be made immediately. * * SPP_PMTUD_ENABLE - This field will enable PMTU * discovery upon the specified address. Note that * if the address feild is empty then all addresses * on the association are effected. * * SPP_PMTUD_DISABLE - This field will disable PMTU * discovery upon the specified address. Note that * if the address feild is empty then all addresses * on the association are effected. Not also that * SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE are mutually * exclusive. Enabling both will have undetermined * results. * * SPP_SACKDELAY_ENABLE - Setting this flag turns * on delayed sack. The time specified in spp_sackdelay * is used to specify the sack delay for this address. Note * that if spp_address is empty then all addresses will * enable delayed sack and take on the sack delay * value specified in spp_sackdelay. * SPP_SACKDELAY_DISABLE - Setting this flag turns * off delayed sack. If the spp_address field is blank then * delayed sack is disabled for the entire association. Note * also that this field is mutually exclusive to * SPP_SACKDELAY_ENABLE, setting both will have undefined * results. * * SPP_IPV6_FLOWLABEL: Setting this flag enables the * setting of the IPV6 flow label value. The value is * contained in the spp_ipv6_flowlabel field. * Upon retrieval, this flag will be set to indicate that * the spp_ipv6_flowlabel field has a valid value returned. * If a specific destination address is set (in the * spp_address field), then the value returned is that of * the address. If just an association is specified (and * no address), then the association's default flow label * is returned. If neither an association nor a destination * is specified, then the socket's default flow label is * returned. For non-IPv6 sockets, this flag will be left * cleared. * * SPP_DSCP: Setting this flag enables the setting of the * Differentiated Services Code Point (DSCP) value * associated with either the association or a specific * address. The value is obtained in the spp_dscp field. * Upon retrieval, this flag will be set to indicate that * the spp_dscp field has a valid value returned. If a * specific destination address is set when called (in the * spp_address field), then that specific destination * address's DSCP value is returned. If just an association * is specified, then the association's default DSCP is * returned. If neither an association nor a destination is * specified, then the socket's default DSCP is returned. * * spp_ipv6_flowlabel * - This field is used in conjunction with the * SPP_IPV6_FLOWLABEL flag and contains the IPv6 flow label. * The 20 least significant bits are used for the flow * label. This setting has precedence over any IPv6-layer * setting. * * spp_dscp - This field is used in conjunction with the SPP_DSCP flag * and contains the DSCP. The 6 most significant bits are * used for the DSCP. This setting has precedence over any * IPv4- or IPv6- layer setting. */ static int sctp_getsockopt_peer_addr_params(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.23. Get or set delayed ack timer (SCTP_DELAYED_SACK) * * This option will effect the way delayed acks are performed. This * option allows you to get or set the delayed ack time, in * milliseconds. It also allows changing the delayed ack frequency. * Changing the frequency to 1 disables the delayed sack algorithm. If * the assoc_id is 0, then this sets or gets the endpoints default * values. If the assoc_id field is non-zero, then the set or get * effects the specified association for the one to many model (the * assoc_id field is ignored by the one to one model). Note that if * sack_delay or sack_freq are 0 when setting this option, then the * current values will remain unchanged. * * struct sctp_sack_info { * sctp_assoc_t sack_assoc_id; * uint32_t sack_delay; * uint32_t sack_freq; * }; * * sack_assoc_id - This parameter, indicates which association the user * is performing an action upon. Note that if this field's value is * zero then the endpoints default value is changed (effecting future * associations only). * * sack_delay - This parameter contains the number of milliseconds that * the user is requesting the delayed ACK timer be set to. Note that * this value is defined in the standard to be between 200 and 500 * milliseconds. * * sack_freq - This parameter contains the number of packets that must * be received before a sack is sent without waiting for the delay * timer to expire. The default value for this is 2, setting this * value to 1 will disable the delayed sack algorithm. */ static int sctp_getsockopt_delayed_ack(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.3 Initialization Parameters (SCTP_INITMSG) * * Applications can specify protocol parameters for the default association * initialization. The option name argument to setsockopt() and getsockopt() * is SCTP_INITMSG. * * Setting initialization parameters is effective only on an unconnected * socket (for UDP-style sockets only future associations are effected * by the change). With TCP-style sockets, this option is inherited by * sockets derived from a listener socket. */ static int sctp_getsockopt_initmsg(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_peer_addrs(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_copy_laddrs(struct sock *sk, __u16 port, void *to, size_t space_left, int *bytes_copied) { … } static int sctp_getsockopt_local_addrs(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* 7.1.10 Set Primary Address (SCTP_PRIMARY_ADDR) * * Requests that the local SCTP stack use the enclosed peer address as * the association primary. The enclosed address must be one of the * association peer's addresses. */ static int sctp_getsockopt_primary_addr(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.11 Set Adaptation Layer Indicator (SCTP_ADAPTATION_LAYER) * * Requests that the local endpoint set the specified Adaptation Layer * Indication parameter for all future INIT and INIT-ACK exchanges. */ static int sctp_getsockopt_adaptation_layer(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * * 7.1.14 Set default send parameters (SCTP_DEFAULT_SEND_PARAM) * * Applications that wish to use the sendto() system call may wish to * specify a default set of parameters that would normally be supplied * through the inclusion of ancillary data. This socket option allows * such an application to set the default sctp_sndrcvinfo structure. * The application that wishes to use this socket option simply passes * in to this call the sctp_sndrcvinfo structure defined in Section * 5.2.2) The input parameters accepted by this call include * sinfo_stream, sinfo_flags, sinfo_ppid, sinfo_context, * sinfo_timetolive. The user must provide the sinfo_assoc_id field in * to this call if the caller is using the UDP model. * * For getsockopt, it get the default sctp_sndrcvinfo structure. */ static int sctp_getsockopt_default_send_param(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* RFC6458, Section 8.1.31. Set/get Default Send Parameters * (SCTP_DEFAULT_SNDINFO) */ static int sctp_getsockopt_default_sndinfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * * 7.1.5 SCTP_NODELAY * * Turn on/off any Nagle-like algorithm. This means that packets are * generally sent as soon as possible and no unnecessary delays are * introduced, at the cost of more packets in the network. Expects an * integer boolean flag. */ static int sctp_getsockopt_nodelay(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * * 7.1.1 SCTP_RTOINFO * * The protocol parameters used to initialize and bound retransmission * timeout (RTO) are tunable. sctp_rtoinfo structure is used to access * and modify these parameters. * All parameters are time values, in milliseconds. A value of 0, when * modifying the parameters, indicates that the current value should not * be changed. * */ static int sctp_getsockopt_rtoinfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * * 7.1.2 SCTP_ASSOCINFO * * This option is used to tune the maximum retransmission attempts * of the association. * Returns an error if the new association retransmission value is * greater than the sum of the retransmission value of the peer. * See [SCTP] for more information. * */ static int sctp_getsockopt_associnfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.16 Set/clear IPv4 mapped addresses (SCTP_I_WANT_MAPPED_V4_ADDR) * * This socket option is a boolean flag which turns on or off mapped V4 * addresses. If this option is turned on and the socket is type * PF_INET6, then IPv4 addresses will be mapped to V6 representation. * If this option is turned off, then no mapping will be done of V4 * addresses and a user will receive both PF_INET6 and PF_INET type * addresses on the socket. */ static int sctp_getsockopt_mappedv4(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.29. Set or Get the default context (SCTP_CONTEXT) * (chapter and verse is quoted at sctp_setsockopt_context()) */ static int sctp_getsockopt_context(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 8.1.16. Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG) * This option will get or set the maximum size to put in any outgoing * SCTP DATA chunk. If a message is larger than this size it will be * fragmented by SCTP into the specified size. Note that the underlying * SCTP implementation may fragment into smaller sized chunks when the * PMTU of the underlying association is smaller than the value set by * the user. The default value for this option is '0' which indicates * the user is NOT limiting fragmentation and only the PMTU will effect * SCTP's choice of DATA chunk size. Note also that values set larger * than the maximum size of an IP datagram will effectively let SCTP * control fragmentation (i.e. the same as setting this option to 0). * * The following structure is used to access and modify this parameter: * * struct sctp_assoc_value { * sctp_assoc_t assoc_id; * uint32_t assoc_value; * }; * * assoc_id: This parameter is ignored for one-to-one style sockets. * For one-to-many style sockets this parameter indicates which * association the user is performing an action upon. Note that if * this field's value is zero then the endpoints default value is * changed (effecting future associations only). * assoc_value: This parameter specifies the maximum size in bytes. */ static int sctp_getsockopt_maxseg(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.24. Get or set fragmented interleave (SCTP_FRAGMENT_INTERLEAVE) * (chapter and verse is quoted at sctp_setsockopt_fragment_interleave()) */ static int sctp_getsockopt_fragment_interleave(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.25. Set or Get the sctp partial delivery point * (chapter and verse is quoted at sctp_setsockopt_partial_delivery_point()) */ static int sctp_getsockopt_partial_delivery_point(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 7.1.28. Set or Get the maximum burst (SCTP_MAX_BURST) * (chapter and verse is quoted at sctp_setsockopt_maxburst()) */ static int sctp_getsockopt_maxburst(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_hmac_ident(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_active_key(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_peer_auth_chunks(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_local_auth_chunks(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 8.2.5. Get the Current Number of Associations (SCTP_GET_ASSOC_NUMBER) * This option gets the current number of associations that are attached * to a one-to-many style socket. The option value is an uint32_t. */ static int sctp_getsockopt_assoc_number(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 8.1.23 SCTP_AUTO_ASCONF * See the corresponding setsockopt entry as description */ static int sctp_getsockopt_auto_asconf(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * 8.2.6. Get the Current Identifiers of Associations * (SCTP_GET_ASSOC_ID_LIST) * * This option gets the current list of SCTP association identifiers of * the SCTP associations handled by a one-to-many style socket. */ static int sctp_getsockopt_assoc_ids(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } /* * SCTP_PEER_ADDR_THLDS * * This option allows us to fetch the partially failed threshold for one or all * transports in an association. See Section 6.1 of: * http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt */ static int sctp_getsockopt_paddr_thresholds(struct sock *sk, char __user *optval, int len, int __user *optlen, bool v2) { … } /* * SCTP_GET_ASSOC_STATS * * This option retrieves local per endpoint statistics. It is modeled * after OpenSolaris' implementation */ static int sctp_getsockopt_assoc_stats(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_recvrcvinfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_recvnxtinfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_pr_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_default_prinfo(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_pr_assocstatus(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_reconfig_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_enable_strreset(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_scheduler(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_scheduler_value(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_interleaving_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_reuse_port(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_event(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_asconf_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_auth_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_ecn_supported(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_pf_expose(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_encap_port(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt_probe_interval(struct sock *sk, int len, char __user *optval, int __user *optlen) { … } static int sctp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen) { … } static bool sctp_bpf_bypass_getsockopt(int level, int optname) { … } static int sctp_hash(struct sock *sk) { … } static void sctp_unhash(struct sock *sk) { … } /* Check if port is acceptable. Possibly find first available port. * * The port hash table (contained in the 'global' SCTP protocol storage * returned by struct sctp_protocol *sctp_get_protocol()). The hash * table is an array of 4096 lists (sctp_bind_hashbucket). Each * list (the list number is the port number hashed out, so as you * would expect from a hash function, all the ports in a given list have * such a number that hashes out to the same list number; you were * expecting that, right?); so each list has a set of ports, with a * link to the socket (struct sock) that uses it, the port number and * a fastreuse flag (FIXME: NPI ipg). */ static struct sctp_bind_bucket *sctp_bucket_create( struct sctp_bind_hashbucket *head, struct net *, unsigned short snum); static int sctp_get_port_local(struct sock *sk, union sctp_addr *addr) { … } /* Assign a 'snum' port to the socket. If snum == 0, an ephemeral * port is requested. */ static int sctp_get_port(struct sock *sk, unsigned short snum) { … } /* * Move a socket to LISTENING state. */ static int sctp_listen_start(struct sock *sk, int backlog) { … } /* * 4.1.3 / 5.1.3 listen() * * By default, new associations are not accepted for UDP style sockets. * An application uses listen() to mark a socket as being able to * accept new associations. * * On TCP style sockets, applications use listen() to ready the SCTP * endpoint for accepting inbound associations. * * On both types of endpoints a backlog of '0' disables listening. * * Move a socket to LISTENING state. */ int sctp_inet_listen(struct socket *sock, int backlog) { … } /* * This function is done by modeling the current datagram_poll() and the * tcp_poll(). Note that, based on these implementations, we don't * lock the socket in this function, even though it seems that, * ideally, locking or some other mechanisms can be used to ensure * the integrity of the counters (sndbuf and wmem_alloc) used * in this place. We assume that we don't need locks either until proven * otherwise. * * Another thing to note is that we include the Async I/O support * here, again, by modeling the current TCP/UDP code. We don't have * a good way to test with it yet. */ __poll_t sctp_poll(struct file *file, struct socket *sock, poll_table *wait) { … } /******************************************************************** * 2nd Level Abstractions ********************************************************************/ static struct sctp_bind_bucket *sctp_bucket_create( struct sctp_bind_hashbucket *head, struct net *net, unsigned short snum) { … } /* Caller must hold hashbucket lock for this tb with local BH disabled */ static void sctp_bucket_destroy(struct sctp_bind_bucket *pp) { … } /* Release this socket's reference to a local port. */ static inline void __sctp_put_port(struct sock *sk) { … } void sctp_put_port(struct sock *sk) { … } /* * The system picks an ephemeral port and choose an address set equivalent * to binding with a wildcard address. * One of those addresses will be the primary address for the association. * This automatically enables the multihoming capability of SCTP. */ static int sctp_autobind(struct sock *sk) { … } /* Parse out IPPROTO_SCTP CMSG headers. Perform only minimal validation. * * From RFC 2292 * 4.2 The cmsghdr Structure * * * When ancillary data is sent or received, any number of ancillary data * objects can be specified by the msg_control and msg_controllen members of * the msghdr structure, because each object is preceded by * a cmsghdr structure defining the object's length (the cmsg_len member). * Historically Berkeley-derived implementations have passed only one object * at a time, but this API allows multiple objects to be * passed in a single call to sendmsg() or recvmsg(). The following example * shows two ancillary data objects in a control buffer. * * |<--------------------------- msg_controllen -------------------------->| * | | * * |<----- ancillary data object ----->|<----- ancillary data object ----->| * * |<---------- CMSG_SPACE() --------->|<---------- CMSG_SPACE() --------->| * | | | * * |<---------- cmsg_len ---------->| |<--------- cmsg_len ----------->| | * * |<--------- CMSG_LEN() --------->| |<-------- CMSG_LEN() ---------->| | * | | | | | * * +-----+-----+-----+--+-----------+--+-----+-----+-----+--+-----------+--+ * |cmsg_|cmsg_|cmsg_|XX| |XX|cmsg_|cmsg_|cmsg_|XX| |XX| * * |len |level|type |XX|cmsg_data[]|XX|len |level|type |XX|cmsg_data[]|XX| * * +-----+-----+-----+--+-----------+--+-----+-----+-----+--+-----------+--+ * ^ * | * * msg_control * points here */ static int sctp_msghdr_parse(const struct msghdr *msg, struct sctp_cmsgs *cmsgs) { … } /* * Wait for a packet.. * Note: This function is the same function as in core/datagram.c * with a few modifications to make lksctp work. */ static int sctp_wait_for_packet(struct sock *sk, int *err, long *timeo_p) { … } /* Receive a datagram. * Note: This is pretty much the same routine as in core/datagram.c * with a few changes to make lksctp work. */ struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, int *err) { … } /* If sndbuf has changed, wake up per association sndbuf waiters. */ static void __sctp_write_space(struct sctp_association *asoc) { … } static void sctp_wake_up_waiters(struct sock *sk, struct sctp_association *asoc) { … } /* Do accounting for the sndbuf space. * Decrement the used sndbuf space of the corresponding association by the * data size which was just transmitted(freed). */ static void sctp_wfree(struct sk_buff *skb) { … } /* Do accounting for the receive space on the socket. * Accounting for the association is done in ulpevent.c * We set this as a destructor for the cloned data skbs so that * accounting is done at the correct time. */ void sctp_sock_rfree(struct sk_buff *skb) { … } /* Helper function to wait for space in the sndbuf. */ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p, size_t msg_len) { … } void sctp_data_ready(struct sock *sk) { … } /* If socket sndbuf has changed, wake up all per association waiters. */ void sctp_write_space(struct sock *sk) { … } /* Is there any sndbuf space available on the socket? * * Note that sk_wmem_alloc is the sum of the send buffers on all of the * associations on the same socket. For a UDP-style socket with * multiple associations, it is possible for it to be "unwriteable" * prematurely. I assume that this is acceptable because * a premature "unwriteable" is better than an accidental "writeable" which * would cause an unwanted block under certain circumstances. For the 1-1 * UDP-style sockets or TCP-style sockets, this code should work. * - Daisy */ static bool sctp_writeable(const struct sock *sk) { … } /* Wait for an association to go into ESTABLISHED state. If timeout is 0, * returns immediately with EINPROGRESS. */ static int sctp_wait_for_connect(struct sctp_association *asoc, long *timeo_p) { … } static int sctp_wait_for_accept(struct sock *sk, long timeo) { … } static void sctp_wait_for_close(struct sock *sk, long timeout) { … } static void sctp_skb_set_owner_r_frag(struct sk_buff *skb, struct sock *sk) { … } void sctp_copy_sock(struct sock *newsk, struct sock *sk, struct sctp_association *asoc) { … } static inline void sctp_copy_descendant(struct sock *sk_to, const struct sock *sk_from) { … } /* Populate the fields of the newsk from the oldsk and migrate the assoc * and its messages to the newsk. */ static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, struct sctp_association *assoc, enum sctp_socket_type type) { … } /* This proto struct describes the ULP interface for SCTP. */ struct proto sctp_prot = …; #if IS_ENABLED(CONFIG_IPV6) static void sctp_v6_destruct_sock(struct sock *sk) { … } static int sctp_v6_init_sock(struct sock *sk) { … } struct proto sctpv6_prot = …; #endif /* IS_ENABLED(CONFIG_IPV6) */
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