// SPDX-License-Identifier: GPL-2.0-only /* PTP classifier */ /* The below program is the bpf_asm (tools/net/) representation of * the opcode array in the ptp_filter structure. * * For convenience, this can easily be altered and reviewed with * bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a * simple file containing the below program: * * ldh [12] ; load ethertype * * ; PTP over UDP over IPv4 over Ethernet * test_ipv4: * jneq #0x800, test_ipv6 ; ETH_P_IP ? * ldb [23] ; load proto * jneq #17, drop_ipv4 ; IPPROTO_UDP ? * ldh [20] ; load frag offset field * jset #0x1fff, drop_ipv4 ; don't allow fragments * ldxb 4*([14]&0xf) ; load IP header len * ldh [x + 16] ; load UDP dst port * jneq #319, drop_ipv4 ; is port PTP_EV_PORT ? * ldh [x + 22] ; load payload * and #0xf ; mask PTP_CLASS_VMASK * or #0x10 ; PTP_CLASS_IPV4 * ret a ; return PTP class * drop_ipv4: ret #0x0 ; PTP_CLASS_NONE * * ; PTP over UDP over IPv6 over Ethernet * test_ipv6: * jneq #0x86dd, test_8021q ; ETH_P_IPV6 ? * ldb [20] ; load proto * jneq #17, drop_ipv6 ; IPPROTO_UDP ? * ldh [56] ; load UDP dst port * jneq #319, drop_ipv6 ; is port PTP_EV_PORT ? * ldh [62] ; load payload * and #0xf ; mask PTP_CLASS_VMASK * or #0x20 ; PTP_CLASS_IPV6 * ret a ; return PTP class * drop_ipv6: ret #0x0 ; PTP_CLASS_NONE * * ; PTP over 802.1Q over Ethernet * test_8021q: * jneq #0x8100, test_ieee1588 ; ETH_P_8021Q ? * ldh [16] ; load inner type * jneq #0x88f7, test_8021q_ipv4 ; ETH_P_1588 ? * ldb [18] ; load payload * and #0x8 ; as we don't have ports here, test * jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these * ldh [18] ; reload payload * and #0xf ; mask PTP_CLASS_VMASK * or #0xc0 ; PTP_CLASS_VLAN|PTP_CLASS_L2 * ret a ; return PTP class * * ; PTP over UDP over IPv4 over 802.1Q over Ethernet * test_8021q_ipv4: * jneq #0x800, test_8021q_ipv6 ; ETH_P_IP ? * ldb [27] ; load proto * jneq #17, drop_8021q_ipv4 ; IPPROTO_UDP ? * ldh [24] ; load frag offset field * jset #0x1fff, drop_8021q_ipv4; don't allow fragments * ldxb 4*([18]&0xf) ; load IP header len * ldh [x + 20] ; load UDP dst port * jneq #319, drop_8021q_ipv4 ; is port PTP_EV_PORT ? * ldh [x + 26] ; load payload * and #0xf ; mask PTP_CLASS_VMASK * or #0x90 ; PTP_CLASS_VLAN|PTP_CLASS_IPV4 * ret a ; return PTP class * drop_8021q_ipv4: ret #0x0 ; PTP_CLASS_NONE * * ; PTP over UDP over IPv6 over 802.1Q over Ethernet * test_8021q_ipv6: * jneq #0x86dd, drop_8021q_ipv6 ; ETH_P_IPV6 ? * ldb [24] ; load proto * jneq #17, drop_8021q_ipv6 ; IPPROTO_UDP ? * ldh [60] ; load UDP dst port * jneq #319, drop_8021q_ipv6 ; is port PTP_EV_PORT ? * ldh [66] ; load payload * and #0xf ; mask PTP_CLASS_VMASK * or #0xa0 ; PTP_CLASS_VLAN|PTP_CLASS_IPV6 * ret a ; return PTP class * drop_8021q_ipv6: ret #0x0 ; PTP_CLASS_NONE * * ; PTP over Ethernet * test_ieee1588: * jneq #0x88f7, drop_ieee1588 ; ETH_P_1588 ? * ldb [14] ; load payload * and #0x8 ; as we don't have ports here, test * jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these * ldh [14] ; reload payload * and #0xf ; mask PTP_CLASS_VMASK * or #0x40 ; PTP_CLASS_L2 * ret a ; return PTP class * drop_ieee1588: ret #0x0 ; PTP_CLASS_NONE */ #include <linux/skbuff.h> #include <linux/filter.h> #include <linux/ptp_classify.h> static struct bpf_prog *ptp_insns __read_mostly; unsigned int ptp_classify_raw(const struct sk_buff *skb) { … } EXPORT_SYMBOL_GPL(…); struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type) { … } EXPORT_SYMBOL_GPL(…); bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type) { … } EXPORT_SYMBOL_GPL(…); void __init ptp_classifier_init(void) { … }
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