lib/packets.h

   1 /*
   2  * Copyright (c) 2008, 2009 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 bool dpid_from_string(const char *s, uint64_t *dpidp);
  30
  31 #define ETH_ADDR_LEN           6
  32
  33 static const uint8_t eth_addr_broadcast[ETH_ADDR_LEN] UNUSED
  34     = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  35
  36 static inline bool eth_addr_is_broadcast(const uint8_t ea[6])
  37 {
  38     return (ea[0] & ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) == 0xff;
  39 }
  40
  41 static inline bool eth_addr_is_multicast(const uint8_t ea[6])
  42 {
  43     return ea[0] & 1;
  44 }
  45 static inline bool eth_addr_is_local(const uint8_t ea[6])
  46 {
  47     /* Local if it is either a locally administered address or a Nicira random
  48      * address. */
  49     return !!(ea[0] & 2)
  50        || (ea[0] == 0x00 && ea[1] == 0x23 && ea[2] == 0x20 && !!(ea[3] & 0x80));
  51 }
  52 static inline bool eth_addr_is_zero(const uint8_t ea[6])
  53 {
  54     return !(ea[0] | ea[1] | ea[2] | ea[3] | ea[4] | ea[5]);
  55 }
  56 static inline bool eth_addr_equals(const uint8_t a[ETH_ADDR_LEN],
  57                                    const uint8_t b[ETH_ADDR_LEN])
  58 {
  59     return !memcmp(a, b, ETH_ADDR_LEN);
  60 }
  61 static inline uint64_t eth_addr_to_uint64(const uint8_t ea[ETH_ADDR_LEN])
  62 {
  63     return (((uint64_t) ea[0] << 40)
  64             | ((uint64_t) ea[1] << 32)
  65             | ((uint64_t) ea[2] << 24)
  66             | ((uint64_t) ea[3] << 16)
  67             | ((uint64_t) ea[4] << 8)
  68             | ea[5]);
  69 }
  70 static inline void eth_addr_from_uint64(uint64_t x, uint8_t ea[ETH_ADDR_LEN])
  71 {
  72     ea[0] = x >> 40;
  73     ea[1] = x >> 32;
  74     ea[2] = x >> 24;
  75     ea[3] = x >> 16;
  76     ea[4] = x >> 8;
  77     ea[5] = x;
  78 }
  79 static inline void eth_addr_mark_random(uint8_t ea[ETH_ADDR_LEN])
  80 {
  81     ea[0] &= ~1;                /* Unicast. */
  82     ea[0] |= 2;                 /* Private. */
  83 }
  84 static inline void eth_addr_random(uint8_t ea[ETH_ADDR_LEN])
  85 {
  86     random_bytes(ea, ETH_ADDR_LEN);
  87     eth_addr_mark_random(ea);
  88 }
  89 static inline void eth_addr_nicira_random(uint8_t ea[ETH_ADDR_LEN])
  90 {
  91     eth_addr_random(ea);
  92
  93     /* Set the OUI to the Nicira one. */
  94     ea[0] = 0x00;
  95     ea[1] = 0x23;
  96     ea[2] = 0x20;
  97
  98     /* Set the top bit to indicate random Nicira address. */
  99     ea[3] |= 0x80;
 100 }
 101 /* Returns true if 'ea' is a reserved multicast address, that a bridge must
 102  * never forward, false otherwise. */
 103 static inline bool eth_addr_is_reserved(const uint8_t ea[ETH_ADDR_LEN])
 104 {
 105     return (ea[0] == 0x01
 106             && ea[1] == 0x80
 107             && ea[2] == 0xc2
 108             && ea[3] == 0x00
 109             && ea[4] == 0x00
 110             && (ea[5] & 0xf0) == 0x00);
 111 }
 112
 113 bool eth_addr_from_string(const char *, uint8_t ea[ETH_ADDR_LEN]);
 114
 115 void compose_benign_packet(struct ofpbuf *, const char *tag,
 116                            uint16_t snap_type,
 117                            const uint8_t eth_src[ETH_ADDR_LEN]);
 118
 119 /* Example:
 120  *
 121  * uint8_t mac[ETH_ADDR_LEN];
 122  *    [...]
 123  * printf("The Ethernet address is "ETH_ADDR_FMT"\n", ETH_ADDR_ARGS(mac));
 124  *
 125  */
 126 #define ETH_ADDR_FMT                                                    \
 127     "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
 128 #define ETH_ADDR_ARGS(ea)                                   \
 129     (ea)[0], (ea)[1], (ea)[2], (ea)[3], (ea)[4], (ea)[5]
 130
 131 /* Example:
 132  *
 133  * char *string = "1 00:11:22:33:44:55 2";
 134  * uint8_t mac[ETH_ADDR_LEN];
 135  * int a, b;
 136  *
 137  * if (sscanf(string, "%d"ETH_ADDR_SCAN_FMT"%d",
 138  *     &a, ETH_ADDR_SCAN_ARGS(mac), &b) == 1 + ETH_ADDR_SCAN_COUNT + 1) {
 139  *     ...
 140  * }
 141  */
 142 #define ETH_ADDR_SCAN_FMT "%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8
 143 #define ETH_ADDR_SCAN_ARGS(ea) \
 144         &(ea)[0], &(ea)[1], &(ea)[2], &(ea)[3], &(ea)[4], &(ea)[5]
 145 #define ETH_ADDR_SCAN_COUNT 6
 146
 147 #define ETH_TYPE_IP            0x0800
 148 #define ETH_TYPE_ARP           0x0806
 149 #define ETH_TYPE_VLAN          0x8100
 150
 151 #define ETH_HEADER_LEN 14
 152 #define ETH_PAYLOAD_MIN 46
 153 #define ETH_PAYLOAD_MAX 1500
 154 #define ETH_TOTAL_MIN (ETH_HEADER_LEN + ETH_PAYLOAD_MIN)
 155 #define ETH_TOTAL_MAX (ETH_HEADER_LEN + ETH_PAYLOAD_MAX)
 156 #define ETH_VLAN_TOTAL_MAX (ETH_HEADER_LEN + VLAN_HEADER_LEN + ETH_PAYLOAD_MAX)
 157 struct eth_header {
 158     uint8_t eth_dst[ETH_ADDR_LEN];
 159     uint8_t eth_src[ETH_ADDR_LEN];
 160     uint16_t eth_type;
 161 } __attribute__((packed));
 162 BUILD_ASSERT_DECL(ETH_HEADER_LEN == sizeof(struct eth_header));
 163
 164 #define LLC_DSAP_SNAP 0xaa
 165 #define LLC_SSAP_SNAP 0xaa
 166 #define LLC_CNTL_SNAP 3
 167
 168 #define LLC_HEADER_LEN 3
 169 struct llc_header {
 170     uint8_t llc_dsap;
 171     uint8_t llc_ssap;
 172     uint8_t llc_cntl;
 173 } __attribute__((packed));
 174 BUILD_ASSERT_DECL(LLC_HEADER_LEN == sizeof(struct llc_header));
 175
 176 #define SNAP_ORG_ETHERNET "\0\0" /* The compiler adds a null byte, so
 177                                     sizeof(SNAP_ORG_ETHERNET) == 3. */
 178 #define SNAP_HEADER_LEN 5
 179 struct snap_header {
 180     uint8_t snap_org[3];
 181     uint16_t snap_type;
 182 } __attribute__((packed));
 183 BUILD_ASSERT_DECL(SNAP_HEADER_LEN == sizeof(struct snap_header));
 184
 185 #define LLC_SNAP_HEADER_LEN (LLC_HEADER_LEN + SNAP_HEADER_LEN)
 186 struct llc_snap_header {
 187     struct llc_header llc;
 188     struct snap_header snap;
 189 } __attribute__((packed));
 190 BUILD_ASSERT_DECL(LLC_SNAP_HEADER_LEN == sizeof(struct llc_snap_header));
 191
 192 #define VLAN_VID_MASK 0x0fff
 193 #define VLAN_PCP_MASK 0xe000
 194
 195 #define VLAN_HEADER_LEN 4
 196 struct vlan_header {
 197     uint16_t vlan_tci;          /* Lowest 12 bits are VLAN ID. */
 198     uint16_t vlan_next_type;
 199 };
 200 BUILD_ASSERT_DECL(VLAN_HEADER_LEN == sizeof(struct vlan_header));
 201
 202 #define VLAN_ETH_HEADER_LEN (ETH_HEADER_LEN + VLAN_HEADER_LEN)
 203 struct vlan_eth_header {
 204     uint8_t veth_dst[ETH_ADDR_LEN];
 205     uint8_t veth_src[ETH_ADDR_LEN];
 206     uint16_t veth_type;         /* Always htons(ETH_TYPE_VLAN). */
 207     uint16_t veth_tci;          /* Lowest 12 bits are VLAN ID. */
 208     uint16_t veth_next_type;
 209 } __attribute__((packed));
 210 BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));
 211
 212 /* The "(void) (ip)[0]" below has no effect on the value, since it's the first
 213  * argument of a comma expression, but it makes sure that 'ip' is a pointer.
 214  * This is useful since a common mistake is to pass an integer instead of a
 215  * pointer to IP_ARGS. */
 216 #define IP_FMT "%"PRIu8".%"PRIu8".%"PRIu8".%"PRIu8
 217 #define IP_ARGS(ip)                             \
 218         ((void) (ip)[0], ((uint8_t *) ip)[0]),  \
 219         ((uint8_t *) ip)[1],                    \
 220         ((uint8_t *) ip)[2],                    \
 221         ((uint8_t *) ip)[3]
 222
 223 #define IP_VER(ip_ihl_ver) ((ip_ihl_ver) >> 4)
 224 #define IP_IHL(ip_ihl_ver) ((ip_ihl_ver) & 15)
 225 #define IP_IHL_VER(ihl, ver) (((ver) << 4) | (ihl))
 226
 227 #define IP_TYPE_ICMP 1
 228 #define IP_TYPE_TCP 6
 229 #define IP_TYPE_UDP 17
 230
 231 #define IP_VERSION 4
 232
 233 #define IP_DONT_FRAGMENT  0x4000 /* Don't fragment. */
 234 #define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
 235 #define IP_FRAG_OFF_MASK  0x1fff /* Fragment offset. */
 236 #define IP_IS_FRAGMENT(ip_frag_off) \
 237         ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))
 238
 239 #define IP_HEADER_LEN 20
 240 struct ip_header {
 241     uint8_t ip_ihl_ver;
 242     uint8_t ip_tos;
 243     uint16_t ip_tot_len;
 244     uint16_t ip_id;
 245     uint16_t ip_frag_off;
 246     uint8_t ip_ttl;
 247     uint8_t ip_proto;
 248     uint16_t ip_csum;
 249     uint32_t ip_src;
 250     uint32_t ip_dst;
 251 };
 252 BUILD_ASSERT_DECL(IP_HEADER_LEN == sizeof(struct ip_header));
 253
 254 #define ICMP_HEADER_LEN 4
 255 struct icmp_header {
 256     uint8_t icmp_type;
 257     uint8_t icmp_code;
 258     uint16_t icmp_csum;
 259 };
 260 BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
 261
 262 #define UDP_HEADER_LEN 8
 263 struct udp_header {
 264     uint16_t udp_src;
 265     uint16_t udp_dst;
 266     uint16_t udp_len;
 267     uint16_t udp_csum;
 268 };
 269 BUILD_ASSERT_DECL(UDP_HEADER_LEN == sizeof(struct udp_header));
 270
 271 #define TCP_FIN 0x01
 272 #define TCP_SYN 0x02
 273 #define TCP_RST 0x04
 274 #define TCP_PSH 0x08
 275 #define TCP_ACK 0x10
 276 #define TCP_URG 0x20
 277
 278 #define TCP_FLAGS(tcp_ctl) (htons(tcp_ctl) & 0x003f)
 279 #define TCP_OFFSET(tcp_ctl) (htons(tcp_ctl) >> 12)
 280
 281 #define TCP_HEADER_LEN 20
 282 struct tcp_header {
 283     uint16_t tcp_src;
 284     uint16_t tcp_dst;
 285     uint32_t tcp_seq;
 286     uint32_t tcp_ack;
 287     uint16_t tcp_ctl;
 288     uint16_t tcp_winsz;
 289     uint16_t tcp_csum;
 290     uint16_t tcp_urg;
 291 };
 292 BUILD_ASSERT_DECL(TCP_HEADER_LEN == sizeof(struct tcp_header));
 293
 294 #define ARP_HRD_ETHERNET 1
 295 #define ARP_PRO_IP 0x0800
 296 #define ARP_OP_REQUEST 1
 297 #define ARP_OP_REPLY 2
 298
 299 #define ARP_ETH_HEADER_LEN 28
 300 struct arp_eth_header {
 301     /* Generic members. */
 302     uint16_t ar_hrd;           /* Hardware type. */
 303     uint16_t ar_pro;           /* Protocol type. */
 304     uint8_t ar_hln;            /* Hardware address length. */
 305     uint8_t ar_pln;            /* Protocol address length. */
 306     uint16_t ar_op;            /* Opcode. */
 307
 308     /* Ethernet+IPv4 specific members. */
 309     uint8_t ar_sha[ETH_ADDR_LEN]; /* Sender hardware address. */
 310     uint32_t ar_spa;           /* Sender protocol address. */
 311     uint8_t ar_tha[ETH_ADDR_LEN]; /* Target hardware address. */
 312     uint32_t ar_tpa;           /* Target protocol address. */
 313 } __attribute__((packed));
 314 BUILD_ASSERT_DECL(ARP_ETH_HEADER_LEN == sizeof(struct arp_eth_header));
 315
 316 #endif /* packets.h */