// SPDX-License-Identifier: GPL-2.0 /* * Management Component Transport Protocol (MCTP) - routing * implementation. * * This is currently based on a simple routing table, with no dst cache. The * number of routes should stay fairly small, so the lookup cost is small. * * Copyright (c) 2021 Code Construct * Copyright (c) 2021 Google */ #include <linux/idr.h> #include <linux/kconfig.h> #include <linux/mctp.h> #include <linux/netdevice.h> #include <linux/rtnetlink.h> #include <linux/skbuff.h> #include <uapi/linux/if_arp.h> #include <net/mctp.h> #include <net/mctpdevice.h> #include <net/netlink.h> #include <net/sock.h> #include <trace/events/mctp.h> static const unsigned int mctp_message_maxlen = …; static const unsigned long mctp_key_lifetime = …; static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev); /* route output callbacks */ static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb) { … } static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb) { … } /* A note on the key allocations. * * struct net->mctp.keys contains our set of currently-allocated keys for * MCTP tag management. The lookup tuple for these is the peer EID, * local EID and MCTP tag. * * In some cases, the peer EID may be MCTP_EID_ANY: for example, when a * broadcast message is sent, we may receive responses from any peer EID. * Because the broadcast dest address is equivalent to ANY, we create * a key with (local = local-eid, peer = ANY). This allows a match on the * incoming broadcast responses from any peer. * * We perform lookups when packets are received, and when tags are allocated * in two scenarios: * * - when a packet is sent, with a locally-owned tag: we need to find an * unused tag value for the (local, peer) EID pair. * * - when a tag is manually allocated: we need to find an unused tag value * for the peer EID, but don't have a specific local EID at that stage. * * in the latter case, on successful allocation, we end up with a tag with * (local = ANY, peer = peer-eid). * * So, the key set allows both a local EID of ANY, as well as a peer EID of * ANY in the lookup tuple. Both may be ANY if we prealloc for a broadcast. * The matching (in mctp_key_match()) during lookup allows the match value to * be ANY in either the dest or source addresses. * * When allocating (+ inserting) a tag, we need to check for conflicts amongst * the existing tag set. This requires macthing either exactly on the local * and peer addresses, or either being ANY. */ static bool mctp_key_match(struct mctp_sk_key *key, unsigned int net, mctp_eid_t local, mctp_eid_t peer, u8 tag) { … } /* returns a key (with key->lock held, and refcounted), or NULL if no such * key exists. */ static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb, unsigned int netid, mctp_eid_t peer, unsigned long *irqflags) __acquires(&key->lock) { … } static struct mctp_sk_key *mctp_key_alloc(struct mctp_sock *msk, unsigned int net, mctp_eid_t local, mctp_eid_t peer, u8 tag, gfp_t gfp) { … } void mctp_key_unref(struct mctp_sk_key *key) { … } static int mctp_key_add(struct mctp_sk_key *key, struct mctp_sock *msk) { … } /* Helper for mctp_route_input(). * We're done with the key; unlock and unref the key. * For the usual case of automatic expiry we remove the key from lists. * In the case that manual allocation is set on a key we release the lock * and local ref, reset reassembly, but don't remove from lists. */ static void __mctp_key_done_in(struct mctp_sk_key *key, struct net *net, unsigned long flags, unsigned long reason) __releases(&key->lock) { … } #ifdef CONFIG_MCTP_FLOWS static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key) { … } static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) { … } #else static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key) {} static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) {} #endif static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb) { … } static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) { … } static unsigned int mctp_route_mtu(struct mctp_route *rt) { … } static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb) { … } /* route alloc/release */ static void mctp_route_release(struct mctp_route *rt) { … } /* returns a route with the refcount at 1 */ static struct mctp_route *mctp_route_alloc(void) { … } unsigned int mctp_default_net(struct net *net) { … } int mctp_default_net_set(struct net *net, unsigned int index) { … } /* tag management */ static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key, struct mctp_sock *msk) { … } /* Allocate a locally-owned tag value for (local, peer), and reserve * it for the socket msk */ struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk, unsigned int netid, mctp_eid_t local, mctp_eid_t peer, bool manual, u8 *tagp) { … } static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk, unsigned int netid, mctp_eid_t daddr, u8 req_tag, u8 *tagp) { … } /* routing lookups */ static bool mctp_rt_match_eid(struct mctp_route *rt, unsigned int net, mctp_eid_t eid) { … } /* compares match, used for duplicate prevention */ static bool mctp_rt_compare_exact(struct mctp_route *rt1, struct mctp_route *rt2) { … } struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, mctp_eid_t daddr) { … } static struct mctp_route *mctp_route_lookup_null(struct net *net, struct net_device *dev) { … } static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb, unsigned int mtu, u8 tag) { … } int mctp_local_output(struct sock *sk, struct mctp_route *rt, struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag) { … } /* route management */ static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start, unsigned int daddr_extent, unsigned int mtu, unsigned char type) { … } static int mctp_route_remove(struct mctp_dev *mdev, mctp_eid_t daddr_start, unsigned int daddr_extent, unsigned char type) { … } int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr) { … } int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr) { … } /* removes all entries for a given device */ void mctp_route_remove_dev(struct mctp_dev *mdev) { … } /* Incoming packet-handling */ static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) { … } static struct packet_type mctp_packet_type = …; /* netlink interface */ static const struct nla_policy rta_mctp_policy[RTA_MAX + 1] = …; /* Common part for RTM_NEWROUTE and RTM_DELROUTE parsing. * tb must hold RTA_MAX+1 elements. */ static int mctp_route_nlparse(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack, struct nlattr **tb, struct rtmsg **rtm, struct mctp_dev **mdev, mctp_eid_t *daddr_start) { … } static const struct nla_policy rta_metrics_policy[RTAX_MAX + 1] = …; static int mctp_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { … } static int mctp_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { … } static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt, u32 portid, u32 seq, int event, unsigned int flags) { … } static int mctp_dump_rtinfo(struct sk_buff *skb, struct netlink_callback *cb) { … } /* net namespace implementation */ static int __net_init mctp_routes_net_init(struct net *net) { … } static void __net_exit mctp_routes_net_exit(struct net *net) { … } static struct pernet_operations mctp_net_ops = …; int __init mctp_routes_init(void) { … } void mctp_routes_exit(void) { … } #if IS_ENABLED(CONFIG_MCTP_TEST) #include "test/route-test.c" #endif
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