net/core/ptp_classifier.c

   1 /* PTP classifier
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10  * General Public License for more details.
  11  */
  12
  13 /* The below program is the bpf_asm (tools/net/) representation of
  14  * the opcode array in the ptp_filter structure.
  15  *
  16  * For convenience, this can easily be altered and reviewed with
  17  * bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a
  18  * simple file containing the below program:
  19  *
  20  * ldh [12]                        ; load ethertype
  21  *
  22  * ; PTP over UDP over IPv4 over Ethernet
  23  * test_ipv4:
  24  *   jneq #0x800, test_ipv6        ; ETH_P_IP ?
  25  *   ldb [23]                      ; load proto
  26  *   jneq #17, drop_ipv4           ; IPPROTO_UDP ?
  27  *   ldh [20]                      ; load frag offset field
  28  *   jset #0x1fff, drop_ipv4       ; don't allow fragments
  29  *   ldxb 4*([14]&0xf)             ; load IP header len
  30  *   ldh [x + 16]                  ; load UDP dst port
  31  *   jneq #319, drop_ipv4          ; is port PTP_EV_PORT ?
  32  *   ldh [x + 22]                  ; load payload
  33  *   and #0xf                      ; mask PTP_CLASS_VMASK
  34  *   or #0x10                      ; PTP_CLASS_IPV4
  35  *   ret a                         ; return PTP class
  36  *   drop_ipv4: ret #0x0           ; PTP_CLASS_NONE
  37  *
  38  * ; PTP over UDP over IPv6 over Ethernet
  39  * test_ipv6:
  40  *   jneq #0x86dd, test_8021q      ; ETH_P_IPV6 ?
  41  *   ldb [20]                      ; load proto
  42  *   jneq #17, drop_ipv6           ; IPPROTO_UDP ?
  43  *   ldh [56]                      ; load UDP dst port
  44  *   jneq #319, drop_ipv6          ; is port PTP_EV_PORT ?
  45  *   ldh [62]                      ; load payload
  46  *   and #0xf                      ; mask PTP_CLASS_VMASK
  47  *   or #0x20                      ; PTP_CLASS_IPV6
  48  *   ret a                         ; return PTP class
  49  *   drop_ipv6: ret #0x0           ; PTP_CLASS_NONE
  50  *
  51  * ; PTP over 802.1Q over Ethernet
  52  * test_8021q:
  53  *   jneq #0x8100, test_ieee1588   ; ETH_P_8021Q ?
  54  *   ldh [16]                      ; load inner type
  55  *   jneq #0x88f7, drop_ieee1588   ; ETH_P_1588 ?
  56  *   ldb [18]                      ; load payload
  57  *   and #0x8                      ; as we don't have ports here, test
  58  *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
  59  *   ldh [18]                      ; reload payload
  60  *   and #0xf                      ; mask PTP_CLASS_VMASK
  61  *   or #0x40                      ; PTP_CLASS_V2_VLAN
  62  *   ret a                         ; return PTP class
  63  *
  64  * ; PTP over Ethernet
  65  * test_ieee1588:
  66  *   jneq #0x88f7, drop_ieee1588   ; ETH_P_1588 ?
  67  *   ldb [14]                      ; load payload
  68  *   and #0x8                      ; as we don't have ports here, test
  69  *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
  70  *   ldh [14]                      ; reload payload
  71  *   and #0xf                      ; mask PTP_CLASS_VMASK
  72  *   or #0x30                      ; PTP_CLASS_L2
  73  *   ret a                         ; return PTP class
  74  *   drop_ieee1588: ret #0x0       ; PTP_CLASS_NONE
  75  */
  76
  77 #include <linux/skbuff.h>
  78 #include <linux/filter.h>
  79 #include <linux/ptp_classify.h>
  80
  81 static struct sk_filter *ptp_insns __read_mostly;
  82
  83 unsigned int ptp_classify_raw(const struct sk_buff *skb)
  84 {
  85         return SK_RUN_FILTER(ptp_insns, skb);
  86 }
  87 EXPORT_SYMBOL_GPL(ptp_classify_raw);
  88
  89 void __init ptp_classifier_init(void)
  90 {
  91         static struct sock_filter ptp_filter[] __initdata = {
  92                 { 0x28,  0,  0, 0x0000000c },
  93                 { 0x15,  0, 12, 0x00000800 },
  94                 { 0x30,  0,  0, 0x00000017 },
  95                 { 0x15,  0,  9, 0x00000011 },
  96                 { 0x28,  0,  0, 0x00000014 },
  97                 { 0x45,  7,  0, 0x00001fff },
  98                 { 0xb1,  0,  0, 0x0000000e },
  99                 { 0x48,  0,  0, 0x00000010 },
 100                 { 0x15,  0,  4, 0x0000013f },
 101                 { 0x48,  0,  0, 0x00000016 },
 102                 { 0x54,  0,  0, 0x0000000f },
 103                 { 0x44,  0,  0, 0x00000010 },
 104                 { 0x16,  0,  0, 0x00000000 },
 105                 { 0x06,  0,  0, 0x00000000 },
 106                 { 0x15,  0,  9, 0x000086dd },
 107                 { 0x30,  0,  0, 0x00000014 },
 108                 { 0x15,  0,  6, 0x00000011 },
 109                 { 0x28,  0,  0, 0x00000038 },
 110                 { 0x15,  0,  4, 0x0000013f },
 111                 { 0x28,  0,  0, 0x0000003e },
 112                 { 0x54,  0,  0, 0x0000000f },
 113                 { 0x44,  0,  0, 0x00000020 },
 114                 { 0x16,  0,  0, 0x00000000 },
 115                 { 0x06,  0,  0, 0x00000000 },
 116                 { 0x15,  0,  9, 0x00008100 },
 117                 { 0x28,  0,  0, 0x00000010 },
 118                 { 0x15,  0, 15, 0x000088f7 },
 119                 { 0x30,  0,  0, 0x00000012 },
 120                 { 0x54,  0,  0, 0x00000008 },
 121                 { 0x15,  0, 12, 0x00000000 },
 122                 { 0x28,  0,  0, 0x00000012 },
 123                 { 0x54,  0,  0, 0x0000000f },
 124                 { 0x44,  0,  0, 0x00000040 },
 125                 { 0x16,  0,  0, 0x00000000 },
 126                 { 0x15,  0,  7, 0x000088f7 },
 127                 { 0x30,  0,  0, 0x0000000e },
 128                 { 0x54,  0,  0, 0x00000008 },
 129                 { 0x15,  0,  4, 0x00000000 },
 130                 { 0x28,  0,  0, 0x0000000e },
 131                 { 0x54,  0,  0, 0x0000000f },
 132                 { 0x44,  0,  0, 0x00000030 },
 133                 { 0x16,  0,  0, 0x00000000 },
 134                 { 0x06,  0,  0, 0x00000000 },
 135         };
 136         struct sock_fprog ptp_prog = {
 137                 .len = ARRAY_SIZE(ptp_filter), .filter = ptp_filter,
 138         };
 139
 140         BUG_ON(sk_unattached_filter_create(&ptp_insns, &ptp_prog));
 141 }