lib/packets.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011 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 <sys/types.h>
  22 #include <netinet/in.h>
  23 #include <stdint.h>
  24 #include <string.h>
  25 #include "compiler.h"
  26 #include "openvswitch/types.h"
  27 #include "random.h"
  28 #include "util.h"
  29
  30 struct ofpbuf;
  31 struct ds;
  32
  33 bool dpid_from_string(const char *s, uint64_t *dpidp);
  34
  35 #define ETH_ADDR_LEN           6
  36
  37 static const uint8_t eth_addr_broadcast[ETH_ADDR_LEN] OVS_UNUSED
  38     = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  39
  40 static const uint8_t eth_addr_stp[ETH_ADDR_LEN] OVS_UNUSED
  41     = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 };
  42
  43 static const uint8_t eth_addr_lacp[ETH_ADDR_LEN] OVS_UNUSED
  44     = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x02 };
  45
  46 static inline bool eth_addr_is_broadcast(const uint8_t ea[6])
  47 {
  48     return (ea[0] & ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) == 0xff;
  49 }
  50
  51 static inline bool eth_addr_is_multicast(const uint8_t ea[6])
  52 {
  53     return ea[0] & 1;
  54 }
  55 static inline bool eth_addr_is_local(const uint8_t ea[6])
  56 {
  57     /* Local if it is either a locally administered address or a Nicira random
  58      * address. */
  59     return ea[0] & 2
  60        || (ea[0] == 0x00 && ea[1] == 0x23 && ea[2] == 0x20 && ea[3] & 0x80);
  61 }
  62 static inline bool eth_addr_is_zero(const uint8_t ea[6])
  63 {
  64     return !(ea[0] | ea[1] | ea[2] | ea[3] | ea[4] | ea[5]);
  65 }
  66 static inline int eth_addr_compare_3way(const uint8_t a[ETH_ADDR_LEN],
  67                                         const uint8_t b[ETH_ADDR_LEN])
  68 {
  69     return memcmp(a, b, ETH_ADDR_LEN);
  70 }
  71 static inline bool eth_addr_equals(const uint8_t a[ETH_ADDR_LEN],
  72                                    const uint8_t b[ETH_ADDR_LEN])
  73 {
  74     return !eth_addr_compare_3way(a, b);
  75 }
  76 static inline uint64_t eth_addr_to_uint64(const uint8_t ea[ETH_ADDR_LEN])
  77 {
  78     return (((uint64_t) ea[0] << 40)
  79             | ((uint64_t) ea[1] << 32)
  80             | ((uint64_t) ea[2] << 24)
  81             | ((uint64_t) ea[3] << 16)
  82             | ((uint64_t) ea[4] << 8)
  83             | ea[5]);
  84 }
  85 static inline void eth_addr_from_uint64(uint64_t x, uint8_t ea[ETH_ADDR_LEN])
  86 {
  87     ea[0] = x >> 40;
  88     ea[1] = x >> 32;
  89     ea[2] = x >> 24;
  90     ea[3] = x >> 16;
  91     ea[4] = x >> 8;
  92     ea[5] = x;
  93 }
  94 static inline void eth_addr_mark_random(uint8_t ea[ETH_ADDR_LEN])
  95 {
  96     ea[0] &= ~1;                /* Unicast. */
  97     ea[0] |= 2;                 /* Private. */
  98 }
  99 static inline void eth_addr_random(uint8_t ea[ETH_ADDR_LEN])
 100 {
 101     random_bytes(ea, ETH_ADDR_LEN);
 102     eth_addr_mark_random(ea);
 103 }
 104 static inline void eth_addr_nicira_random(uint8_t ea[ETH_ADDR_LEN])
 105 {
 106     eth_addr_random(ea);
 107
 108     /* Set the OUI to the Nicira one. */
 109     ea[0] = 0x00;
 110     ea[1] = 0x23;
 111     ea[2] = 0x20;
 112
 113     /* Set the top bit to indicate random Nicira address. */
 114     ea[3] |= 0x80;
 115 }
 116 /* Returns true if 'ea' is a reserved multicast address, that a bridge must
 117  * never forward, false otherwise. */
 118 static inline bool eth_addr_is_reserved(const uint8_t ea[ETH_ADDR_LEN])
 119 {
 120     return (ea[0] == 0x01
 121             && ea[1] == 0x80
 122             && ea[2] == 0xc2
 123             && ea[3] == 0x00
 124             && ea[4] == 0x00
 125             && (ea[5] & 0xf0) == 0x00);
 126 }
 127
 128 bool eth_addr_from_string(const char *, uint8_t ea[ETH_ADDR_LEN]);
 129
 130 void compose_benign_packet(struct ofpbuf *, const char *tag,
 131                            uint16_t snap_type,
 132                            const uint8_t eth_src[ETH_ADDR_LEN]);
 133
 134 void eth_push_vlan(struct ofpbuf *, ovs_be16 tci);
 135
 136 /* Example:
 137  *
 138  * uint8_t mac[ETH_ADDR_LEN];
 139  *    [...]
 140  * printf("The Ethernet address is "ETH_ADDR_FMT"\n", ETH_ADDR_ARGS(mac));
 141  *
 142  */
 143 #define ETH_ADDR_FMT                                                    \
 144     "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
 145 #define ETH_ADDR_ARGS(ea)                                   \
 146     (ea)[0], (ea)[1], (ea)[2], (ea)[3], (ea)[4], (ea)[5]
 147
 148 /* Example:
 149  *
 150  * char *string = "1 00:11:22:33:44:55 2";
 151  * uint8_t mac[ETH_ADDR_LEN];
 152  * int a, b;
 153  *
 154  * if (sscanf(string, "%d"ETH_ADDR_SCAN_FMT"%d",
 155  *     &a, ETH_ADDR_SCAN_ARGS(mac), &b) == 1 + ETH_ADDR_SCAN_COUNT + 1) {
 156  *     ...
 157  * }
 158  */
 159 #define ETH_ADDR_SCAN_FMT "%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8":%"SCNx8
 160 #define ETH_ADDR_SCAN_ARGS(ea) \
 161         &(ea)[0], &(ea)[1], &(ea)[2], &(ea)[3], &(ea)[4], &(ea)[5]
 162 #define ETH_ADDR_SCAN_COUNT 6
 163
 164 #define ETH_TYPE_IP            0x0800
 165 #define ETH_TYPE_ARP           0x0806
 166 #define ETH_TYPE_VLAN          0x8100
 167 #define ETH_TYPE_IPV6          0x86dd
 168 #define ETH_TYPE_LACP          0x8809
 169
 170 /* Minimum value for an Ethernet type.  Values below this are IEEE 802.2 frame
 171  * lengths. */
 172 #define ETH_TYPE_MIN           0x600
 173
 174 #define ETH_HEADER_LEN 14
 175 #define ETH_PAYLOAD_MIN 46
 176 #define ETH_PAYLOAD_MAX 1500
 177 #define ETH_TOTAL_MIN (ETH_HEADER_LEN + ETH_PAYLOAD_MIN)
 178 #define ETH_TOTAL_MAX (ETH_HEADER_LEN + ETH_PAYLOAD_MAX)
 179 #define ETH_VLAN_TOTAL_MAX (ETH_HEADER_LEN + VLAN_HEADER_LEN + ETH_PAYLOAD_MAX)
 180 struct eth_header {
 181     uint8_t eth_dst[ETH_ADDR_LEN];
 182     uint8_t eth_src[ETH_ADDR_LEN];
 183     ovs_be16 eth_type;
 184 } __attribute__((packed));
 185 BUILD_ASSERT_DECL(ETH_HEADER_LEN == sizeof(struct eth_header));
 186
 187 #define LLC_DSAP_SNAP 0xaa
 188 #define LLC_SSAP_SNAP 0xaa
 189 #define LLC_CNTL_SNAP 3
 190
 191 #define LLC_HEADER_LEN 3
 192 struct llc_header {
 193     uint8_t llc_dsap;
 194     uint8_t llc_ssap;
 195     uint8_t llc_cntl;
 196 } __attribute__((packed));
 197 BUILD_ASSERT_DECL(LLC_HEADER_LEN == sizeof(struct llc_header));
 198
 199 #define SNAP_ORG_ETHERNET "\0\0" /* The compiler adds a null byte, so
 200                                     sizeof(SNAP_ORG_ETHERNET) == 3. */
 201 #define SNAP_HEADER_LEN 5
 202 struct snap_header {
 203     uint8_t snap_org[3];
 204     ovs_be16 snap_type;
 205 } __attribute__((packed));
 206 BUILD_ASSERT_DECL(SNAP_HEADER_LEN == sizeof(struct snap_header));
 207
 208 #define LLC_SNAP_HEADER_LEN (LLC_HEADER_LEN + SNAP_HEADER_LEN)
 209 struct llc_snap_header {
 210     struct llc_header llc;
 211     struct snap_header snap;
 212 } __attribute__((packed));
 213 BUILD_ASSERT_DECL(LLC_SNAP_HEADER_LEN == sizeof(struct llc_snap_header));
 214
 215 #define VLAN_VID_MASK 0x0fff
 216 #define VLAN_VID_SHIFT 0
 217
 218 #define VLAN_PCP_MASK 0xe000
 219 #define VLAN_PCP_SHIFT 13
 220
 221 #define VLAN_CFI 0x1000
 222
 223 /* Given the vlan_tci field from an 802.1Q header, in network byte order,
 224  * returns the VLAN ID in host byte order. */
 225 static inline uint16_t
 226 vlan_tci_to_vid(ovs_be16 vlan_tci)
 227 {
 228     return (ntohs(vlan_tci) & VLAN_VID_MASK) >> VLAN_VID_SHIFT;
 229 }
 230
 231 /* Given the vlan_tci field from an 802.1Q header, in network byte order,
 232  * returns the priority code point (PCP) in host byte order. */
 233 static inline int
 234 vlan_tci_to_pcp(ovs_be16 vlan_tci)
 235 {
 236     return (ntohs(vlan_tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT;
 237 }
 238
 239 #define VLAN_HEADER_LEN 4
 240 struct vlan_header {
 241     ovs_be16 vlan_tci;          /* Lowest 12 bits are VLAN ID. */
 242     ovs_be16 vlan_next_type;
 243 };
 244 BUILD_ASSERT_DECL(VLAN_HEADER_LEN == sizeof(struct vlan_header));
 245
 246 #define VLAN_ETH_HEADER_LEN (ETH_HEADER_LEN + VLAN_HEADER_LEN)
 247 struct vlan_eth_header {
 248     uint8_t veth_dst[ETH_ADDR_LEN];
 249     uint8_t veth_src[ETH_ADDR_LEN];
 250     ovs_be16 veth_type;         /* Always htons(ETH_TYPE_VLAN). */
 251     ovs_be16 veth_tci;          /* Lowest 12 bits are VLAN ID. */
 252     ovs_be16 veth_next_type;
 253 } __attribute__((packed));
 254 BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));
 255
 256 /* The "(void) (ip)[0]" below has no effect on the value, since it's the first
 257  * argument of a comma expression, but it makes sure that 'ip' is a pointer.
 258  * This is useful since a common mistake is to pass an integer instead of a
 259  * pointer to IP_ARGS. */
 260 #define IP_FMT "%"PRIu8".%"PRIu8".%"PRIu8".%"PRIu8
 261 #define IP_ARGS(ip)                             \
 262         ((void) (ip)[0], ((uint8_t *) ip)[0]),  \
 263         ((uint8_t *) ip)[1],                    \
 264         ((uint8_t *) ip)[2],                    \
 265         ((uint8_t *) ip)[3]
 266
 267 /* Example:
 268  *
 269  * char *string = "1 33.44.55.66 2";
 270  * ovs_be32 ip;
 271  * int a, b;
 272  *
 273  * if (sscanf(string, "%d"IP_SCAN_FMT"%d",
 274  *     &a, IP_SCAN_ARGS(&ip), &b) == 1 + IP_SCAN_COUNT + 1) {
 275  *     ...
 276  * }
 277  */
 278 #define IP_SCAN_FMT "%"SCNu8".%"SCNu8".%"SCNu8".%"SCNu8
 279 #define IP_SCAN_ARGS(ip)                                    \
 280         ((void) (ovs_be32) *(ip), &((uint8_t *) ip)[0]),    \
 281         &((uint8_t *) ip)[1],                               \
 282         &((uint8_t *) ip)[2],                               \
 283         &((uint8_t *) ip)[3]
 284 #define IP_SCAN_COUNT 4
 285
 286 /* Returns true if 'netmask' is a CIDR netmask, that is, if it consists of N
 287  * high-order 1-bits and 32-N low-order 0-bits. */
 288 static inline bool
 289 ip_is_cidr(ovs_be32 netmask)
 290 {
 291     uint32_t x = ~ntohl(netmask);
 292     return !(x & (x + 1));
 293 }
 294 static inline bool
 295 ip_is_multicast(ovs_be32 ip)
 296 {
 297     return (ip & htonl(0xf0000000)) == htonl(0xe0000000);
 298 }
 299 int ip_count_cidr_bits(ovs_be32 netmask);
 300 void ip_format_masked(ovs_be32 ip, ovs_be32 mask, struct ds *);
 301
 302 #define IP_VER(ip_ihl_ver) ((ip_ihl_ver) >> 4)
 303 #define IP_IHL(ip_ihl_ver) ((ip_ihl_ver) & 15)
 304 #define IP_IHL_VER(ihl, ver) (((ver) << 4) | (ihl))
 305
 306 /* TOS fields. */
 307 #define IP_ECN_MASK 0x03
 308 #define IP_DSCP_MASK 0xfc
 309
 310 #define IP_VERSION 4
 311
 312 #define IP_DONT_FRAGMENT  0x4000 /* Don't fragment. */
 313 #define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
 314 #define IP_FRAG_OFF_MASK  0x1fff /* Fragment offset. */
 315 #define IP_IS_FRAGMENT(ip_frag_off) \
 316         ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))
 317
 318 #define IP_HEADER_LEN 20
 319 struct ip_header {
 320     uint8_t ip_ihl_ver;
 321     uint8_t ip_tos;
 322     ovs_be16 ip_tot_len;
 323     ovs_be16 ip_id;
 324     ovs_be16 ip_frag_off;
 325     uint8_t ip_ttl;
 326     uint8_t ip_proto;
 327     ovs_be16 ip_csum;
 328     ovs_be32 ip_src;
 329     ovs_be32 ip_dst;
 330 };
 331 BUILD_ASSERT_DECL(IP_HEADER_LEN == sizeof(struct ip_header));
 332
 333 #define ICMP_HEADER_LEN 4
 334 struct icmp_header {
 335     uint8_t icmp_type;
 336     uint8_t icmp_code;
 337     ovs_be16 icmp_csum;
 338 };
 339 BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
 340
 341 #define UDP_HEADER_LEN 8
 342 struct udp_header {
 343     ovs_be16 udp_src;
 344     ovs_be16 udp_dst;
 345     ovs_be16 udp_len;
 346     ovs_be16 udp_csum;
 347 };
 348 BUILD_ASSERT_DECL(UDP_HEADER_LEN == sizeof(struct udp_header));
 349
 350 #define TCP_FIN 0x01
 351 #define TCP_SYN 0x02
 352 #define TCP_RST 0x04
 353 #define TCP_PSH 0x08
 354 #define TCP_ACK 0x10
 355 #define TCP_URG 0x20
 356
 357 #define TCP_FLAGS(tcp_ctl) (ntohs(tcp_ctl) & 0x003f)
 358 #define TCP_OFFSET(tcp_ctl) (ntohs(tcp_ctl) >> 12)
 359
 360 #define TCP_HEADER_LEN 20
 361 struct tcp_header {
 362     ovs_be16 tcp_src;
 363     ovs_be16 tcp_dst;
 364     ovs_be32 tcp_seq;
 365     ovs_be32 tcp_ack;
 366     ovs_be16 tcp_ctl;
 367     ovs_be16 tcp_winsz;
 368     ovs_be16 tcp_csum;
 369     ovs_be16 tcp_urg;
 370 };
 371 BUILD_ASSERT_DECL(TCP_HEADER_LEN == sizeof(struct tcp_header));
 372
 373 #define ARP_HRD_ETHERNET 1
 374 #define ARP_PRO_IP 0x0800
 375 #define ARP_OP_REQUEST 1
 376 #define ARP_OP_REPLY 2
 377
 378 #define ARP_ETH_HEADER_LEN 28
 379 struct arp_eth_header {
 380     /* Generic members. */
 381     ovs_be16 ar_hrd;           /* Hardware type. */
 382     ovs_be16 ar_pro;           /* Protocol type. */
 383     uint8_t ar_hln;            /* Hardware address length. */
 384     uint8_t ar_pln;            /* Protocol address length. */
 385     ovs_be16 ar_op;            /* Opcode. */
 386
 387     /* Ethernet+IPv4 specific members. */
 388     uint8_t ar_sha[ETH_ADDR_LEN]; /* Sender hardware address. */
 389     ovs_be32 ar_spa;           /* Sender protocol address. */
 390     uint8_t ar_tha[ETH_ADDR_LEN]; /* Target hardware address. */
 391     ovs_be32 ar_tpa;           /* Target protocol address. */
 392 } __attribute__((packed));
 393 BUILD_ASSERT_DECL(ARP_ETH_HEADER_LEN == sizeof(struct arp_eth_header));
 394
 395 /* The IPv6 flow label is in the lower 20 bits of the first 32-bit word. */
 396 #define IPV6_LABEL_MASK 0x000fffff
 397
 398 /* Example:
 399  *
 400  * char *string = "1 ::1 2";
 401  * char ipv6_s[IPV6_SCAN_LEN + 1];
 402  * struct in6_addr ipv6;
 403  *
 404  * if (sscanf(string, "%d"IPV6_SCAN_FMT"%d", &a, ipv6_s, &b) == 3
 405  *     && inet_pton(AF_INET6, ipv6_s, &ipv6) == 1) {
 406  *     ...
 407  * }
 408  */
 409 #define IPV6_SCAN_FMT "%46[0123456789abcdefABCDEF:.]"
 410 #define IPV6_SCAN_LEN 46
 411
 412 extern const struct in6_addr in6addr_exact;
 413 #define IN6ADDR_EXACT_INIT { { { 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, \
 414                                  0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff } } }
 415
 416 static inline bool ipv6_addr_equals(const struct in6_addr *a,
 417                                     const struct in6_addr *b)
 418 {
 419 #ifdef IN6_ARE_ADDR_EQUAL
 420     return IN6_ARE_ADDR_EQUAL(a, b);
 421 #else
 422     return !memcmp(a, b, sizeof(*a));
 423 #endif
 424 }
 425
 426 static inline bool ipv6_mask_is_any(const struct in6_addr *mask) {
 427     return ipv6_addr_equals(mask, &in6addr_any);
 428 }
 429
 430 static inline bool ipv6_mask_is_exact(const struct in6_addr *mask) {
 431     return ipv6_addr_equals(mask, &in6addr_exact);
 432 }
 433
 434 void format_ipv6_addr(char *addr_str, const struct in6_addr *addr);
 435 void print_ipv6_addr(struct ds *string, const struct in6_addr *addr);
 436 void print_ipv6_masked(struct ds *string, const struct in6_addr *addr,
 437                        const struct in6_addr *mask);
 438 struct in6_addr ipv6_addr_bitand(const struct in6_addr *src,
 439                                  const struct in6_addr *mask);
 440 struct in6_addr ipv6_create_mask(int mask);
 441 int ipv6_count_cidr_bits(const struct in6_addr *netmask);
 442 bool ipv6_is_cidr(const struct in6_addr *netmask);
 443
 444 void *eth_compose(struct ofpbuf *, const uint8_t eth_dst[ETH_ADDR_LEN],
 445                   const uint8_t eth_src[ETH_ADDR_LEN], uint16_t eth_type,
 446                   size_t size);
 447 void *snap_compose(struct ofpbuf *, const uint8_t eth_dst[ETH_ADDR_LEN],
 448                    const uint8_t eth_src[ETH_ADDR_LEN],
 449                    unsigned int oui, uint16_t snap_type, size_t size);
 450
 451 #endif /* packets.h */