linux/net/core/ptp_classifier.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-only
   2/* PTP classifier
   3 */
   4
   5/* The below program is the bpf_asm (tools/net/) representation of
   6 * the opcode array in the ptp_filter structure.
   7 *
   8 * For convenience, this can easily be altered and reviewed with
   9 * bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a
  10 * simple file containing the below program:
  11 *
  12 * ldh [12]                        ; load ethertype
  13 *
  14 * ; PTP over UDP over IPv4 over Ethernet
  15 * test_ipv4:
  16 *   jneq #0x800, test_ipv6        ; ETH_P_IP ?
  17 *   ldb [23]                      ; load proto
  18 *   jneq #17, drop_ipv4           ; IPPROTO_UDP ?
  19 *   ldh [20]                      ; load frag offset field
  20 *   jset #0x1fff, drop_ipv4       ; don't allow fragments
  21 *   ldxb 4*([14]&0xf)             ; load IP header len
  22 *   ldh [x + 16]                  ; load UDP dst port
  23 *   jneq #319, drop_ipv4          ; is port PTP_EV_PORT ?
  24 *   ldh [x + 22]                  ; load payload
  25 *   and #0xf                      ; mask PTP_CLASS_VMASK
  26 *   or #0x10                      ; PTP_CLASS_IPV4
  27 *   ret a                         ; return PTP class
  28 *   drop_ipv4: ret #0x0           ; PTP_CLASS_NONE
  29 *
  30 * ; PTP over UDP over IPv6 over Ethernet
  31 * test_ipv6:
  32 *   jneq #0x86dd, test_8021q      ; ETH_P_IPV6 ?
  33 *   ldb [20]                      ; load proto
  34 *   jneq #17, drop_ipv6           ; IPPROTO_UDP ?
  35 *   ldh [56]                      ; load UDP dst port
  36 *   jneq #319, drop_ipv6          ; is port PTP_EV_PORT ?
  37 *   ldh [62]                      ; load payload
  38 *   and #0xf                      ; mask PTP_CLASS_VMASK
  39 *   or #0x20                      ; PTP_CLASS_IPV6
  40 *   ret a                         ; return PTP class
  41 *   drop_ipv6: ret #0x0           ; PTP_CLASS_NONE
  42 *
  43 * ; PTP over 802.1Q over Ethernet
  44 * test_8021q:
  45 *   jneq #0x8100, test_ieee1588   ; ETH_P_8021Q ?
  46 *   ldh [16]                      ; load inner type
  47 *   jneq #0x88f7, test_8021q_ipv4 ; ETH_P_1588 ?
  48 *   ldb [18]                      ; load payload
  49 *   and #0x8                      ; as we don't have ports here, test
  50 *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
  51 *   ldh [18]                      ; reload payload
  52 *   and #0xf                      ; mask PTP_CLASS_VMASK
  53 *   or #0xc0                      ; PTP_CLASS_VLAN|PTP_CLASS_L2
  54 *   ret a                         ; return PTP class
  55 *
  56 * ; PTP over UDP over IPv4 over 802.1Q over Ethernet
  57 * test_8021q_ipv4:
  58 *   jneq #0x800, test_8021q_ipv6  ; ETH_P_IP ?
  59 *   ldb [27]                      ; load proto
  60 *   jneq #17, drop_8021q_ipv4     ; IPPROTO_UDP ?
  61 *   ldh [24]                      ; load frag offset field
  62 *   jset #0x1fff, drop_8021q_ipv4; don't allow fragments
  63 *   ldxb 4*([18]&0xf)             ; load IP header len
  64 *   ldh [x + 20]                  ; load UDP dst port
  65 *   jneq #319, drop_8021q_ipv4    ; is port PTP_EV_PORT ?
  66 *   ldh [x + 26]                  ; load payload
  67 *   and #0xf                      ; mask PTP_CLASS_VMASK
  68 *   or #0x90                      ; PTP_CLASS_VLAN|PTP_CLASS_IPV4
  69 *   ret a                         ; return PTP class
  70 *   drop_8021q_ipv4: ret #0x0     ; PTP_CLASS_NONE
  71 *
  72 * ; PTP over UDP over IPv6 over 802.1Q over Ethernet
  73 * test_8021q_ipv6:
  74 *   jneq #0x86dd, drop_8021q_ipv6 ; ETH_P_IPV6 ?
  75 *   ldb [24]                      ; load proto
  76 *   jneq #17, drop_8021q_ipv6           ; IPPROTO_UDP ?
  77 *   ldh [60]                      ; load UDP dst port
  78 *   jneq #319, drop_8021q_ipv6          ; is port PTP_EV_PORT ?
  79 *   ldh [66]                      ; load payload
  80 *   and #0xf                      ; mask PTP_CLASS_VMASK
  81 *   or #0xa0                      ; PTP_CLASS_VLAN|PTP_CLASS_IPV6
  82 *   ret a                         ; return PTP class
  83 *   drop_8021q_ipv6: ret #0x0     ; PTP_CLASS_NONE
  84 *
  85 * ; PTP over Ethernet
  86 * test_ieee1588:
  87 *   jneq #0x88f7, drop_ieee1588   ; ETH_P_1588 ?
  88 *   ldb [14]                      ; load payload
  89 *   and #0x8                      ; as we don't have ports here, test
  90 *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
  91 *   ldh [14]                      ; reload payload
  92 *   and #0xf                      ; mask PTP_CLASS_VMASK
  93 *   or #0x40                      ; PTP_CLASS_L2
  94 *   ret a                         ; return PTP class
  95 *   drop_ieee1588: ret #0x0       ; PTP_CLASS_NONE
  96 */
  97
  98#include <linux/skbuff.h>
  99#include <linux/filter.h>
 100#include <linux/ptp_classify.h>
 101
 102static struct bpf_prog *ptp_insns __read_mostly;
 103
 104unsigned int ptp_classify_raw(const struct sk_buff *skb)
 105{
 106        return BPF_PROG_RUN(ptp_insns, skb);
 107}
 108EXPORT_SYMBOL_GPL(ptp_classify_raw);
 109
 110struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type)
 111{
 112        u8 *ptr = skb_mac_header(skb);
 113
 114        if (type & PTP_CLASS_VLAN)
 115                ptr += VLAN_HLEN;
 116
 117        switch (type & PTP_CLASS_PMASK) {
 118        case PTP_CLASS_IPV4:
 119                ptr += IPV4_HLEN(ptr) + UDP_HLEN;
 120                break;
 121        case PTP_CLASS_IPV6:
 122                ptr += IP6_HLEN + UDP_HLEN;
 123                break;
 124        case PTP_CLASS_L2:
 125                break;
 126        default:
 127                return NULL;
 128        }
 129
 130        ptr += ETH_HLEN;
 131
 132        /* Ensure that the entire header is present in this packet. */
 133        if (ptr + sizeof(struct ptp_header) > skb->data + skb->len)
 134                return NULL;
 135
 136        return (struct ptp_header *)ptr;
 137}
 138EXPORT_SYMBOL_GPL(ptp_parse_header);
 139
 140void __init ptp_classifier_init(void)
 141{
 142        static struct sock_filter ptp_filter[] __initdata = {
 143                { 0x28,  0,  0, 0x0000000c },
 144                { 0x15,  0, 12, 0x00000800 },
 145                { 0x30,  0,  0, 0x00000017 },
 146                { 0x15,  0,  9, 0x00000011 },
 147                { 0x28,  0,  0, 0x00000014 },
 148                { 0x45,  7,  0, 0x00001fff },
 149                { 0xb1,  0,  0, 0x0000000e },
 150                { 0x48,  0,  0, 0x00000010 },
 151                { 0x15,  0,  4, 0x0000013f },
 152                { 0x48,  0,  0, 0x00000016 },
 153                { 0x54,  0,  0, 0x0000000f },
 154                { 0x44,  0,  0, 0x00000010 },
 155                { 0x16,  0,  0, 0x00000000 },
 156                { 0x06,  0,  0, 0x00000000 },
 157                { 0x15,  0,  9, 0x000086dd },
 158                { 0x30,  0,  0, 0x00000014 },
 159                { 0x15,  0,  6, 0x00000011 },
 160                { 0x28,  0,  0, 0x00000038 },
 161                { 0x15,  0,  4, 0x0000013f },
 162                { 0x28,  0,  0, 0x0000003e },
 163                { 0x54,  0,  0, 0x0000000f },
 164                { 0x44,  0,  0, 0x00000020 },
 165                { 0x16,  0,  0, 0x00000000 },
 166                { 0x06,  0,  0, 0x00000000 },
 167                { 0x15,  0, 32, 0x00008100 },
 168                { 0x28,  0,  0, 0x00000010 },
 169                { 0x15,  0,  7, 0x000088f7 },
 170                { 0x30,  0,  0, 0x00000012 },
 171                { 0x54,  0,  0, 0x00000008 },
 172                { 0x15,  0, 35, 0x00000000 },
 173                { 0x28,  0,  0, 0x00000012 },
 174                { 0x54,  0,  0, 0x0000000f },
 175                { 0x44,  0,  0, 0x000000c0 },
 176                { 0x16,  0,  0, 0x00000000 },
 177                { 0x15,  0, 12, 0x00000800 },
 178                { 0x30,  0,  0, 0x0000001b },
 179                { 0x15,  0,  9, 0x00000011 },
 180                { 0x28,  0,  0, 0x00000018 },
 181                { 0x45,  7,  0, 0x00001fff },
 182                { 0xb1,  0,  0, 0x00000012 },
 183                { 0x48,  0,  0, 0x00000014 },
 184                { 0x15,  0,  4, 0x0000013f },
 185                { 0x48,  0,  0, 0x0000001a },
 186                { 0x54,  0,  0, 0x0000000f },
 187                { 0x44,  0,  0, 0x00000090 },
 188                { 0x16,  0,  0, 0x00000000 },
 189                { 0x06,  0,  0, 0x00000000 },
 190                { 0x15,  0,  8, 0x000086dd },
 191                { 0x30,  0,  0, 0x00000018 },
 192                { 0x15,  0,  6, 0x00000011 },
 193                { 0x28,  0,  0, 0x0000003c },
 194                { 0x15,  0,  4, 0x0000013f },
 195                { 0x28,  0,  0, 0x00000042 },
 196                { 0x54,  0,  0, 0x0000000f },
 197                { 0x44,  0,  0, 0x000000a0 },
 198                { 0x16,  0,  0, 0x00000000 },
 199                { 0x06,  0,  0, 0x00000000 },
 200                { 0x15,  0,  7, 0x000088f7 },
 201                { 0x30,  0,  0, 0x0000000e },
 202                { 0x54,  0,  0, 0x00000008 },
 203                { 0x15,  0,  4, 0x00000000 },
 204                { 0x28,  0,  0, 0x0000000e },
 205                { 0x54,  0,  0, 0x0000000f },
 206                { 0x44,  0,  0, 0x00000040 },
 207                { 0x16,  0,  0, 0x00000000 },
 208                { 0x06,  0,  0, 0x00000000 },
 209        };
 210        struct sock_fprog_kern ptp_prog;
 211
 212        ptp_prog.len = ARRAY_SIZE(ptp_filter);
 213        ptp_prog.filter = ptp_filter;
 214
 215        BUG_ON(bpf_prog_create(&ptp_insns, &ptp_prog));
 216}
 217