trafgen_l2.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Subject to the GPL, version 2.
   4  */
   5
   6 #include <net/if_arp.h>
   7 #include <linux/if_ether.h>
   8
   9 #include "die.h"
  10 #include "built_in.h"
  11 #include "trafgen_l2.h"
  12 #include "trafgen_proto.h"
  13
  14 static struct proto_field eth_fields[] = {
  15         { .id = ETH_DST_ADDR, .len = 6, },
  16         { .id = ETH_SRC_ADDR, .len = 6, .offset = 6 },
  17         { .id = ETH_TYPE,     .len = 2, .offset = 12 },
  18 };
  19
  20 static uint16_t pid_to_eth(enum proto_id pid)
  21 {
  22         switch (pid) {
  23         case PROTO_ARP:
  24                 return ETH_P_ARP;
  25         case PROTO_IP4:
  26                 return ETH_P_IP;
  27         case PROTO_IP6:
  28                 return ETH_P_IPV6;
  29         case PROTO_MPLS:
  30                 return ETH_P_MPLS_UC;
  31         case PROTO_VLAN:
  32                 return ETH_P_8021Q;
  33         case PROTO_PAUSE:
  34                 return ETH_P_PAUSE;
  35         default:
  36                 bug();
  37         }
  38 }
  39
  40 static void eth_set_next_proto(struct proto_hdr *hdr, enum proto_id pid)
  41 {
  42         proto_field_set_default_be16(hdr, ETH_TYPE, pid_to_eth(pid));
  43 }
  44
  45 static void eth_header_init(struct proto_hdr *hdr)
  46 {
  47         proto_header_fields_add(hdr, eth_fields, array_size(eth_fields));
  48
  49         proto_field_set_default_dev_mac(hdr, ETH_SRC_ADDR);
  50 }
  51
  52 static const struct proto_ops eth_proto_ops = {
  53         .id             = PROTO_ETH,
  54         .layer          = PROTO_L2,
  55         .header_init    = eth_header_init,
  56         .set_next_proto = eth_set_next_proto,
  57 };
  58
  59 static struct proto_field pause_fields[] = {
  60         { .id = PAUSE_OPCODE,   .len = 2, .offset = 0 },
  61         { .id = PAUSE_TIME,     .len = 2, .offset = 2 },
  62 };
  63
  64 static void pause_header_init(struct proto_hdr *hdr)
  65 {
  66         uint8_t eth_dst[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x01 };
  67
  68         struct proto_hdr *lower;
  69
  70         lower = proto_lower_default_add(hdr, PROTO_ETH);
  71         proto_field_set_default_bytes(lower, ETH_DST_ADDR, eth_dst);
  72
  73         proto_header_fields_add(hdr, pause_fields, array_size(pause_fields));
  74         proto_field_set_default_be16(hdr, PAUSE_OPCODE, 0x1);
  75 }
  76
  77 static struct proto_ops pause_proto_ops = {
  78         .id             = PROTO_PAUSE,
  79         .layer          = PROTO_L2,
  80         .header_init    = pause_header_init,
  81 };
  82
  83 static struct proto_field vlan_fields[] = {
  84         /* TPID overlaps with Ethernet header and points to ether type */
  85         { .id = VLAN_TPID, .len = 2, .offset = -2 },
  86         { .id = VLAN_TCI,  .len = 2, .offset = 0 },
  87         { .id = VLAN_PCP,  .len = 2, .offset = 0, .shift = 13, .mask = 0xe000 },
  88         { .id = VLAN_DEI,  .len = 2, .offset = 0, .shift = 12, .mask = 0x1000 },
  89         { .id = VLAN_VID,  .len = 2, .offset = 0, .shift = 0,  .mask = 0xfff },
  90         /* Original ether type is stored after VLAN header */
  91         { .id = VLAN_ETYPE, .len = 2, .offset = 2 },
  92 };
  93
  94 static void vlan_header_init(struct proto_hdr *hdr)
  95 {
  96         struct proto_hdr *lower = proto_lower_default_add(hdr, PROTO_ETH);
  97         uint16_t lower_etype = 0;
  98
  99         proto_header_fields_add(hdr, vlan_fields, array_size(vlan_fields));
 100
 101         if (lower->ops->id == PROTO_ETH)
 102                 lower_etype = proto_field_get_u16(lower, ETH_TYPE);
 103         else if (lower->ops->id == PROTO_VLAN)
 104                 lower_etype = proto_field_get_u16(lower, VLAN_ETYPE);
 105
 106         proto_field_set_be16(hdr, VLAN_ETYPE, lower_etype);
 107         proto_field_set_default_be16(hdr, VLAN_TPID, pid_to_eth(hdr->ops->id));
 108 }
 109
 110 static void vlan_set_next_proto(struct proto_hdr *hdr, enum proto_id pid)
 111 {
 112         if (pid != PROTO_VLAN)
 113                 proto_field_set_be16(hdr, VLAN_ETYPE, pid_to_eth(pid));
 114 }
 115
 116 static const struct proto_ops vlan_proto_ops = {
 117         .id             = PROTO_VLAN,
 118         .layer          = PROTO_L2,
 119         .header_init    = vlan_header_init,
 120         .set_next_proto = vlan_set_next_proto,
 121 };
 122
 123 static struct proto_field arp_fields[] = {
 124         { .id = ARP_HTYPE, .len = 2 },
 125         { .id = ARP_PTYPE, .len = 2, .offset = 2 },
 126         { .id = ARP_HLEN,  .len = 1, .offset = 4 },
 127         { .id = ARP_PLEN,  .len = 1, .offset = 5 },
 128         { .id = ARP_OPER,  .len = 2, .offset = 6 },
 129         { .id = ARP_SHA,   .len = 6, .offset = 8 },
 130         { .id = ARP_SPA,   .len = 4, .offset = 14 },
 131         { .id = ARP_THA,   .len = 6, .offset = 18 },
 132         { .id = ARP_TPA,   .len = 4, .offset = 24 },
 133 };
 134
 135 static void arp_header_init(struct proto_hdr *hdr)
 136 {
 137         struct proto_hdr *lower = proto_lower_default_add(hdr, PROTO_ETH);
 138
 139         if (lower->ops->id == PROTO_ETH) {
 140                 const uint8_t bcast[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 141
 142                 proto_field_set_default_bytes(lower, ETH_DST_ADDR, bcast);
 143         }
 144
 145         proto_header_fields_add(hdr, arp_fields, array_size(arp_fields));
 146
 147         /* Generate Announce request by default */
 148         proto_field_set_default_be16(hdr, ARP_HTYPE, ARPHRD_ETHER);
 149         proto_field_set_default_be16(hdr, ARP_PTYPE, ETH_P_IP);
 150         proto_field_set_default_u8(hdr, ARP_HLEN, 6);
 151         proto_field_set_default_u8(hdr, ARP_PLEN, 4);
 152         proto_field_set_default_be16(hdr, ARP_OPER, ARPOP_REQUEST);
 153         proto_field_set_default_dev_mac(hdr, ARP_SHA);
 154         proto_field_set_default_dev_ipv4(hdr, ARP_SPA);
 155         proto_field_set_default_dev_ipv4(hdr, ARP_TPA);
 156 }
 157
 158 static const struct proto_ops arp_proto_ops = {
 159         .id             = PROTO_ARP,
 160         .layer          = PROTO_L2,
 161         .header_init    = arp_header_init,
 162 };
 163
 164 static struct proto_field mpls_fields[] = {
 165         { .id = MPLS_LABEL, .len = 4, .shift = 12, .mask = 0xfffff000 },
 166         { .id = MPLS_TC,    .len = 4, .shift = 9,  .mask = 0xe00 },
 167         { .id = MPLS_LAST,  .len = 4, .shift = 8,  .mask = 0x100 },
 168         { .id = MPLS_TTL,   .len = 4, .shift = 0,  .mask = 0xff },
 169 };
 170
 171 static void mpls_header_init(struct proto_hdr *hdr)
 172 {
 173         proto_lower_default_add(hdr, PROTO_ETH);
 174
 175         proto_header_fields_add(hdr, mpls_fields, array_size(mpls_fields));
 176
 177         proto_field_set_default_be32(hdr, MPLS_LAST, 1);
 178 }
 179
 180 static void mpls_set_next_proto(struct proto_hdr *hdr, enum proto_id pid)
 181 {
 182         if (pid == PROTO_MPLS)
 183                 proto_field_set_default_be32(hdr, MPLS_LAST, 0);
 184 }
 185
 186 static const struct proto_ops mpls_proto_ops = {
 187         .id             = PROTO_MPLS,
 188         .layer          = PROTO_L2,
 189         .header_init    = mpls_header_init,
 190         .set_next_proto = mpls_set_next_proto,
 191 };
 192
 193 void protos_l2_init(void)
 194 {
 195         proto_ops_register(&eth_proto_ops);
 196         proto_ops_register(&pause_proto_ops);
 197         proto_ops_register(&vlan_proto_ops);
 198         proto_ops_register(&arp_proto_ops);
 199         proto_ops_register(&mpls_proto_ops);
 200 }