lib/packets.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef PACKETS_H
  18 #define PACKETS_H 1
  19
  20 #include <inttypes.h>
  21 #include <stdint.h>
  22 #include <string.h>
  23 #include "compiler.h"
  24 #include "random.h"
  25 #include "util.h"
  26
  27 struct ofpbuf;
  28
  29 #define ETH_ADDR_LEN           6
  30
  31 static const uint8_t eth_addr_broadcast[ETH_ADDR_LEN] OVS_UNUSED
  32     = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  33
  34 static inline bool eth_addr_is_broadcast(const uint8_t ea[6])
  35 {
  36     return (ea[0] & ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) == 0xff;
  37 }
  38
  39 /* Returns true if 'ea' is an Ethernet address used for virtual interfaces
  40  * under XenServer.  Generally the actual Ethernet address is FE:FF:FF:FF:FF:FF
  41  * but it can be FE:FE:FE:FE:FE:FE in some cases. */
  42 static inline bool eth_addr_is_vif(const uint8_t ea[6])
  43 {
  44     return ea[0] == 0xfe && (ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) >= 0xfe;
  45 }
  46
  47 static inline bool eth_addr_is_multicast(const uint8_t ea[6])
  48 {
  49     return ea[0] & 1;
  50 }
  51 static inline bool eth_addr_is_local(const uint8_t ea[6])
  52 {
  53     return ea[0] & 2;
  54 }
  55 static inline bool eth_addr_is_zero(const uint8_t ea[6])
  56 {
  57     return !(ea[0] | ea[1] | ea[2] | ea[3] | ea[4] | ea[5]);
  58 }
  59 static inline bool eth_addr_equals(const uint8_t a[ETH_ADDR_LEN],
  60                                    const uint8_t b[ETH_ADDR_LEN])
  61 {
  62     return !memcmp(a, b, ETH_ADDR_LEN);
  63 }
  64 static inline uint64_t eth_addr_to_uint64(const uint8_t ea[ETH_ADDR_LEN])
  65 {
  66     return (((uint64_t) ea[0] << 40)
  67             | ((uint64_t) ea[1] << 32)
  68             | ((uint64_t) ea[2] << 24)
  69             | ((uint64_t) ea[3] << 16)
  70             | ((uint64_t) ea[4] << 8)
  71             | ea[5]);
  72 }
  73 static inline void eth_addr_from_uint64(uint64_t x, uint8_t ea[ETH_ADDR_LEN])
  74 {
  75     ea[0] = x >> 40;
  76     ea[1] = x >> 32;
  77     ea[2] = x >> 24;
  78     ea[3] = x >> 16;
  79     ea[4] = x >> 8;
  80     ea[5] = x;
  81 }
  82 static inline void eth_addr_mark_random(uint8_t ea[ETH_ADDR_LEN])
  83 {
  84     ea[0] &= ~1;                /* Unicast. */
  85     ea[0] |= 2;                 /* Private. */
  86 }
  87 static inline void eth_addr_random(uint8_t ea[ETH_ADDR_LEN])
  88 {
  89     random_bytes(ea, ETH_ADDR_LEN);
  90     eth_addr_mark_random(ea);
  91 }
  92 /* Returns true if 'ea' is a reserved multicast address, that a bridge must
  93  * never forward, false otherwise. */
  94 static inline bool eth_addr_is_reserved(const uint8_t ea[ETH_ADDR_LEN])
  95 {
  96     return (ea[0] == 0x01
  97             && ea[1] == 0x80
  98             && ea[2] == 0xc2
  99             && ea[3] == 0x00
 100             && ea[4] == 0x00
 101             && (ea[5] & 0xf0) == 0x00);
 102 }
 103
 104 void compose_benign_packet(struct ofpbuf *, const char *tag,
 105                            uint16_t snap_type,
 106                            const uint8_t eth_src[ETH_ADDR_LEN]);
 107
 108 /* Example:
 109  *
 110  * uint8_t mac[ETH_ADDR_LEN];
 111  *    [...]
 112  * printf("The Ethernet address is "ETH_ADDR_FMT"\n", ETH_ADDR_ARGS(mac));
 113  *
 114  */
 115 #define ETH_ADDR_FMT                                                    \
 116     "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
 117 #define ETH_ADDR_ARGS(ea)                                   \
 118     (ea)[0], (ea)[1], (ea)[2], (ea)[3], (ea)[4], (ea)[5]
 119
 120 /* Example:
 121  *
 122  * char *string = "1 00:11:22:33:44:55 2";
 123  * uint8_t mac[ETH_ADDR_LEN];
 124  * int a, b;
 125  *
 126  * if (sscanf(string, "%d"ETH_ADDR_SCAN_FMT"%d",
 127  *     &a, ETH_ADDR_SCAN_ARGS(mac), &b) == 1 + ETH_ADDR_SCAN_COUNT + 1) {
 128  *     ...
 129  * }
 130  */
 131 #define ETH_ADDR_SCAN_FMT "%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8
 132 #define ETH_ADDR_SCAN_ARGS(ea) \
 133         &(ea)[0], &(ea)[1], &(ea)[2], &(ea)[3], &(ea)[4], &(ea)[5]
 134 #define ETH_ADDR_SCAN_COUNT 6
 135
 136 #define ETH_TYPE_IP            0x0800
 137 #define ETH_TYPE_ARP           0x0806
 138 #define ETH_TYPE_VLAN          0x8100
 139
 140 #define ETH_HEADER_LEN 14
 141 #define ETH_PAYLOAD_MIN 46
 142 #define ETH_PAYLOAD_MAX 1500
 143 #define ETH_TOTAL_MIN (ETH_HEADER_LEN + ETH_PAYLOAD_MIN)
 144 #define ETH_TOTAL_MAX (ETH_HEADER_LEN + ETH_PAYLOAD_MAX)
 145 #define ETH_VLAN_TOTAL_MAX (ETH_HEADER_LEN + VLAN_HEADER_LEN + ETH_PAYLOAD_MAX)
 146 struct eth_header {
 147     uint8_t eth_dst[ETH_ADDR_LEN];
 148     uint8_t eth_src[ETH_ADDR_LEN];
 149     uint16_t eth_type;
 150 } __attribute__((packed));
 151 BUILD_ASSERT_DECL(ETH_HEADER_LEN == sizeof(struct eth_header));
 152
 153 #define LLC_DSAP_SNAP 0xaa
 154 #define LLC_SSAP_SNAP 0xaa
 155 #define LLC_CNTL_SNAP 3
 156
 157 #define LLC_HEADER_LEN 3
 158 struct llc_header {
 159     uint8_t llc_dsap;
 160     uint8_t llc_ssap;
 161     uint8_t llc_cntl;
 162 } __attribute__((packed));
 163 BUILD_ASSERT_DECL(LLC_HEADER_LEN == sizeof(struct llc_header));
 164
 165 #define SNAP_ORG_ETHERNET "\0\0" /* The compiler adds a null byte, so
 166                                     sizeof(SNAP_ORG_ETHERNET) == 3. */
 167 #define SNAP_HEADER_LEN 5
 168 struct snap_header {
 169     uint8_t snap_org[3];
 170     uint16_t snap_type;
 171 } __attribute__((packed));
 172 BUILD_ASSERT_DECL(SNAP_HEADER_LEN == sizeof(struct snap_header));
 173
 174 #define LLC_SNAP_HEADER_LEN (LLC_HEADER_LEN + SNAP_HEADER_LEN)
 175 struct llc_snap_header {
 176     struct llc_header llc;
 177     struct snap_header snap;
 178 } __attribute__((packed));
 179 BUILD_ASSERT_DECL(LLC_SNAP_HEADER_LEN == sizeof(struct llc_snap_header));
 180
 181 #define VLAN_VID_MASK 0x0fff
 182 #define VLAN_PCP_MASK 0xe000
 183
 184 #define VLAN_HEADER_LEN 4
 185 struct vlan_header {
 186     uint16_t vlan_tci;          /* Lowest 12 bits are VLAN ID. */
 187     uint16_t vlan_next_type;
 188 };
 189 BUILD_ASSERT_DECL(VLAN_HEADER_LEN == sizeof(struct vlan_header));
 190
 191 #define VLAN_ETH_HEADER_LEN (ETH_HEADER_LEN + VLAN_HEADER_LEN)
 192 struct vlan_eth_header {
 193     uint8_t veth_dst[ETH_ADDR_LEN];
 194     uint8_t veth_src[ETH_ADDR_LEN];
 195     uint16_t veth_type;         /* Always htons(ETH_TYPE_VLAN). */
 196     uint16_t veth_tci;          /* Lowest 12 bits are VLAN ID. */
 197     uint16_t veth_next_type;
 198 } __attribute__((packed));
 199 BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));
 200
 201 /* The "(void) (ip)[0]" below has no effect on the value, since it's the first
 202  * argument of a comma expression, but it makes sure that 'ip' is a pointer.
 203  * This is useful since a common mistake is to pass an integer instead of a
 204  * pointer to IP_ARGS. */
 205 #define IP_FMT "%"PRIu8".%"PRIu8".%"PRIu8".%"PRIu8
 206 #define IP_ARGS(ip)                             \
 207         ((void) (ip)[0], ((uint8_t *) ip)[0]),  \
 208         ((uint8_t *) ip)[1],                    \
 209         ((uint8_t *) ip)[2],                    \
 210         ((uint8_t *) ip)[3]
 211
 212 #define IP_VER(ip_ihl_ver) ((ip_ihl_ver) >> 4)
 213 #define IP_IHL(ip_ihl_ver) ((ip_ihl_ver) & 15)
 214 #define IP_IHL_VER(ihl, ver) (((ver) << 4) | (ihl))
 215
 216 #define IP_TYPE_ICMP 1
 217 #define IP_TYPE_TCP 6
 218 #define IP_TYPE_UDP 17
 219
 220 #define IP_VERSION 4
 221
 222 #define IP_DONT_FRAGMENT  0x4000 /* Don't fragment. */
 223 #define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
 224 #define IP_FRAG_OFF_MASK  0x1fff /* Fragment offset. */
 225 #define IP_IS_FRAGMENT(ip_frag_off) \
 226         ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))
 227
 228 #define IP_HEADER_LEN 20
 229 struct ip_header {
 230     uint8_t ip_ihl_ver;
 231     uint8_t ip_tos;
 232     uint16_t ip_tot_len;
 233     uint16_t ip_id;
 234     uint16_t ip_frag_off;
 235     uint8_t ip_ttl;
 236     uint8_t ip_proto;
 237     uint16_t ip_csum;
 238     uint32_t ip_src;
 239     uint32_t ip_dst;
 240 };
 241 BUILD_ASSERT_DECL(IP_HEADER_LEN == sizeof(struct ip_header));
 242
 243 #define ICMP_HEADER_LEN 4
 244 struct icmp_header {
 245     uint8_t icmp_type;
 246     uint8_t icmp_code;
 247     uint16_t icmp_csum;
 248 };
 249 BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
 250
 251 #define UDP_HEADER_LEN 8
 252 struct udp_header {
 253     uint16_t udp_src;
 254     uint16_t udp_dst;
 255     uint16_t udp_len;
 256     uint16_t udp_csum;
 257 };
 258 BUILD_ASSERT_DECL(UDP_HEADER_LEN == sizeof(struct udp_header));
 259
 260 #define TCP_FIN 0x01
 261 #define TCP_SYN 0x02
 262 #define TCP_RST 0x04
 263 #define TCP_PSH 0x08
 264 #define TCP_ACK 0x10
 265 #define TCP_URG 0x20
 266
 267 #define TCP_FLAGS(tcp_ctl) (htons(tcp_ctl) & 0x003f)
 268 #define TCP_OFFSET(tcp_ctl) (htons(tcp_ctl) >> 12)
 269
 270 #define TCP_HEADER_LEN 20
 271 struct tcp_header {
 272     uint16_t tcp_src;
 273     uint16_t tcp_dst;
 274     uint32_t tcp_seq;
 275     uint32_t tcp_ack;
 276     uint16_t tcp_ctl;
 277     uint16_t tcp_winsz;
 278     uint16_t tcp_csum;
 279     uint16_t tcp_urg;
 280 };
 281 BUILD_ASSERT_DECL(TCP_HEADER_LEN == sizeof(struct tcp_header));
 282
 283 #define ARP_HRD_ETHERNET 1
 284 #define ARP_PRO_IP 0x0800
 285 #define ARP_OP_REQUEST 1
 286 #define ARP_OP_REPLY 2
 287
 288 #define ARP_ETH_HEADER_LEN 28
 289 struct arp_eth_header {
 290     /* Generic members. */
 291     uint16_t ar_hrd;           /* Hardware type. */
 292     uint16_t ar_pro;           /* Protocol type. */
 293     uint8_t ar_hln;            /* Hardware address length. */
 294     uint8_t ar_pln;            /* Protocol address length. */
 295     uint16_t ar_op;            /* Opcode. */
 296
 297     /* Ethernet+IPv4 specific members. */
 298     uint8_t ar_sha[ETH_ADDR_LEN]; /* Sender hardware address. */
 299     uint32_t ar_spa;           /* Sender protocol address. */
 300     uint8_t ar_tha[ETH_ADDR_LEN]; /* Target hardware address. */
 301     uint32_t ar_tpa;           /* Target protocol address. */
 302 } __attribute__((packed));
 303 BUILD_ASSERT_DECL(ARP_ETH_HEADER_LEN == sizeof(struct arp_eth_header));
 304
 305 #endif /* packets.h */