2 * Copyright (c) 2009, 2010, 2011 Nicira Networks.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
20 #include <arpa/inet.h>
21 #include <sys/socket.h>
22 #include <netinet/in.h>
24 #include "byte-order.h"
26 #include "dynamic-string.h"
29 const struct in6_addr in6addr_exact = IN6ADDR_EXACT_INIT;
31 /* Parses 's' as a 16-digit hexadecimal number representing a datapath ID. On
32 * success stores the dpid into '*dpidp' and returns true, on failure stores 0
33 * into '*dpidp' and returns false.
35 * Rejects an all-zeros dpid as invalid. */
37 dpid_from_string(const char *s, uint64_t *dpidp)
39 *dpidp = (strlen(s) == 16 && strspn(s, "0123456789abcdefABCDEF") == 16
40 ? strtoull(s, NULL, 16)
46 eth_addr_from_string(const char *s, uint8_t ea[ETH_ADDR_LEN])
48 if (sscanf(s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(ea))
49 == ETH_ADDR_SCAN_COUNT) {
52 memset(ea, 0, ETH_ADDR_LEN);
57 /* Fills 'b' with an 802.2 SNAP packet with Ethernet source address 'eth_src',
58 * the Nicira OUI as SNAP organization and 'snap_type' as SNAP type. The text
59 * string in 'tag' is enclosed as the packet payload.
61 * This function is used by Open vSwitch to compose packets in cases where
62 * context is important but content doesn't (or shouldn't) matter. For this
63 * purpose, 'snap_type' should be a random number and 'tag' should be an
64 * English phrase that explains the purpose of the packet. (The English phrase
65 * gives hapless admins running Wireshark the opportunity to figure out what's
68 compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
69 const uint8_t eth_src[ETH_ADDR_LEN])
71 size_t tag_size = strlen(tag) + 1;
74 payload = snap_compose(b, eth_addr_broadcast, eth_src, 0x002320, snap_type,
75 tag_size + ETH_ADDR_LEN);
76 memcpy(payload, tag, tag_size);
77 memcpy(payload + tag_size, eth_src, ETH_ADDR_LEN);
80 /* Insert VLAN header according to given TCI. Packet passed must be Ethernet
81 * packet. Ignores the CFI bit of 'tci' using 0 instead.
83 * Also sets 'packet->l2' to point to the new Ethernet header. */
85 eth_push_vlan(struct ofpbuf *packet, ovs_be16 tci)
87 struct eth_header *eh = packet->data;
88 struct vlan_eth_header *veh;
90 /* Insert new 802.1Q header. */
91 struct vlan_eth_header tmp;
92 memcpy(tmp.veth_dst, eh->eth_dst, ETH_ADDR_LEN);
93 memcpy(tmp.veth_src, eh->eth_src, ETH_ADDR_LEN);
94 tmp.veth_type = htons(ETH_TYPE_VLAN);
95 tmp.veth_tci = tci & htons(~VLAN_CFI);
96 tmp.veth_next_type = eh->eth_type;
98 veh = ofpbuf_push_uninit(packet, VLAN_HEADER_LEN);
99 memcpy(veh, &tmp, sizeof tmp);
101 packet->l2 = packet->data;
104 /* Removes outermost VLAN header (if any is present) from 'packet'.
106 * 'packet->l2' must initially point to 'packet''s Ethernet header. */
108 eth_pop_vlan(struct ofpbuf *packet)
110 struct vlan_eth_header *veh = packet->l2;
111 if (packet->size >= sizeof *veh
112 && veh->veth_type == htons(ETH_TYPE_VLAN)) {
113 struct eth_header tmp;
115 memcpy(tmp.eth_dst, veh->veth_dst, ETH_ADDR_LEN);
116 memcpy(tmp.eth_src, veh->veth_src, ETH_ADDR_LEN);
117 tmp.eth_type = veh->veth_next_type;
119 ofpbuf_pull(packet, VLAN_HEADER_LEN);
120 packet->l2 = (char*)packet->l2 + VLAN_HEADER_LEN;
121 memcpy(packet->data, &tmp, sizeof tmp);
125 /* Converts hex digits in 'hex' to an Ethernet packet in '*packetp'. The
126 * caller must free '*packetp'. On success, returns NULL. On failure, returns
127 * an error message and stores NULL in '*packetp'. */
129 eth_from_hex(const char *hex, struct ofpbuf **packetp)
131 struct ofpbuf *packet;
133 packet = *packetp = ofpbuf_new(strlen(hex) / 2);
135 if (ofpbuf_put_hex(packet, hex, NULL)[0] != '\0') {
136 ofpbuf_delete(packet);
138 return "Trailing garbage in packet data";
141 if (packet->size < ETH_HEADER_LEN) {
142 ofpbuf_delete(packet);
144 return "Packet data too short for Ethernet";
150 /* Given the IP netmask 'netmask', returns the number of bits of the IP address
151 * that it specifies, that is, the number of 1-bits in 'netmask'. 'netmask'
152 * must be a CIDR netmask (see ip_is_cidr()). */
154 ip_count_cidr_bits(ovs_be32 netmask)
156 assert(ip_is_cidr(netmask));
157 return 32 - ctz(ntohl(netmask));
161 ip_format_masked(ovs_be32 ip, ovs_be32 mask, struct ds *s)
163 ds_put_format(s, IP_FMT, IP_ARGS(&ip));
164 if (mask != htonl(UINT32_MAX)) {
165 if (ip_is_cidr(mask)) {
166 ds_put_format(s, "/%d", ip_count_cidr_bits(mask));
168 ds_put_format(s, "/"IP_FMT, IP_ARGS(&mask));
174 /* Stores the string representation of the IPv6 address 'addr' into the
175 * character array 'addr_str', which must be at least INET6_ADDRSTRLEN
178 format_ipv6_addr(char *addr_str, const struct in6_addr *addr)
180 inet_ntop(AF_INET6, addr, addr_str, INET6_ADDRSTRLEN);
184 print_ipv6_addr(struct ds *string, const struct in6_addr *addr)
188 ds_reserve(string, string->length + INET6_ADDRSTRLEN);
190 dst = string->string + string->length;
191 format_ipv6_addr(dst, addr);
192 string->length += strlen(dst);
196 print_ipv6_masked(struct ds *s, const struct in6_addr *addr,
197 const struct in6_addr *mask)
199 print_ipv6_addr(s, addr);
200 if (mask && !ipv6_mask_is_exact(mask)) {
201 if (ipv6_is_cidr(mask)) {
202 int cidr_bits = ipv6_count_cidr_bits(mask);
203 ds_put_format(s, "/%d", cidr_bits);
206 print_ipv6_addr(s, mask);
211 struct in6_addr ipv6_addr_bitand(const struct in6_addr *a,
212 const struct in6_addr *b)
218 for (i=0; i<4; i++) {
219 dst.s6_addr32[i] = a->s6_addr32[i] & b->s6_addr32[i];
222 for (i=0; i<16; i++) {
223 dst.s6_addr[i] = a->s6_addr[i] & b->s6_addr[i];
230 /* Returns an in6_addr consisting of 'mask' high-order 1-bits and 128-N
231 * low-order 0-bits. */
233 ipv6_create_mask(int mask)
235 struct in6_addr netmask;
236 uint8_t *netmaskp = &netmask.s6_addr[0];
238 memset(&netmask, 0, sizeof netmask);
246 *netmaskp = 0xff << (8 - mask);
252 /* Given the IPv6 netmask 'netmask', returns the number of bits of the IPv6
253 * address that it specifies, that is, the number of 1-bits in 'netmask'.
254 * 'netmask' must be a CIDR netmask (see ipv6_is_cidr()). */
256 ipv6_count_cidr_bits(const struct in6_addr *netmask)
260 const uint8_t *netmaskp = &netmask->s6_addr[0];
262 assert(ipv6_is_cidr(netmask));
264 for (i=0; i<16; i++) {
265 if (netmaskp[i] == 0xff) {
270 for(nm = netmaskp[i]; nm; nm <<= 1) {
281 /* Returns true if 'netmask' is a CIDR netmask, that is, if it consists of N
282 * high-order 1-bits and 128-N low-order 0-bits. */
284 ipv6_is_cidr(const struct in6_addr *netmask)
286 const uint8_t *netmaskp = &netmask->s6_addr[0];
289 for (i=0; i<16; i++) {
290 if (netmaskp[i] != 0xff) {
291 uint8_t x = ~netmaskp[i];
306 /* Populates 'b' with an Ethernet II packet headed with the given 'eth_dst',
307 * 'eth_src' and 'eth_type' parameters. A payload of 'size' bytes is allocated
308 * in 'b' and returned. This payload may be populated with appropriate
309 * information by the caller. Sets 'b''s 'l2' and 'l3' pointers to the
310 * Ethernet header and payload respectively.
312 * The returned packet has enough headroom to insert an 802.1Q VLAN header if
315 eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN],
316 const uint8_t eth_src[ETH_ADDR_LEN], uint16_t eth_type,
320 struct eth_header *eth;
324 ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN + size);
325 ofpbuf_reserve(b, VLAN_HEADER_LEN);
326 eth = ofpbuf_put_uninit(b, ETH_HEADER_LEN);
327 data = ofpbuf_put_uninit(b, size);
329 memcpy(eth->eth_dst, eth_dst, ETH_ADDR_LEN);
330 memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
331 eth->eth_type = htons(eth_type);
339 /* Populates 'b' with an Ethernet LLC+SNAP packet headed with the given
340 * 'eth_dst', 'eth_src', 'snap_org', and 'snap_type'. A payload of 'size'
341 * bytes is allocated in 'b' and returned. This payload may be populated with
342 * appropriate information by the caller.
344 * The returned packet has enough headroom to insert an 802.1Q VLAN header if
347 snap_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN],
348 const uint8_t eth_src[ETH_ADDR_LEN],
349 unsigned int oui, uint16_t snap_type, size_t size)
351 struct eth_header *eth;
352 struct llc_snap_header *llc_snap;
355 /* Compose basic packet structure. (We need the payload size to stick into
356 * the 802.2 header.) */
358 ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN
359 + LLC_SNAP_HEADER_LEN + size);
360 ofpbuf_reserve(b, VLAN_HEADER_LEN);
361 eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN);
362 llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN);
363 payload = ofpbuf_put_uninit(b, size);
365 /* Compose 802.2 header. */
366 memcpy(eth->eth_dst, eth_dst, ETH_ADDR_LEN);
367 memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
368 eth->eth_type = htons(b->size - ETH_HEADER_LEN);
370 /* Compose LLC, SNAP headers. */
371 llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
372 llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
373 llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
374 llc_snap->snap.snap_org[0] = oui >> 16;
375 llc_snap->snap.snap_org[1] = oui >> 8;
376 llc_snap->snap.snap_org[2] = oui;
377 llc_snap->snap.snap_type = htons(snap_type);
383 packet_set_ipv4_addr(struct ofpbuf *packet, ovs_be32 *addr, ovs_be32 new_addr)
385 struct ip_header *nh = packet->l3;
387 if (nh->ip_proto == IPPROTO_TCP && packet->l7) {
388 struct tcp_header *th = packet->l4;
390 th->tcp_csum = recalc_csum32(th->tcp_csum, *addr, new_addr);
391 } else if (nh->ip_proto == IPPROTO_UDP && packet->l7) {
392 struct udp_header *uh = packet->l4;
395 uh->udp_csum = recalc_csum32(uh->udp_csum, *addr, new_addr);
397 uh->udp_csum = htons(0xffff);
401 nh->ip_csum = recalc_csum32(nh->ip_csum, *addr, new_addr);
405 /* Modifies the IPv4 header fields of 'packet' to be consistent with 'src',
406 * 'dst', 'tos', and 'ttl'. Updates 'packet''s L4 checksums as appropriate.
407 * 'packet' must contain a valid IPv4 packet with correctly populated l[347]
410 packet_set_ipv4(struct ofpbuf *packet, ovs_be32 src, ovs_be32 dst,
411 uint8_t tos, uint8_t ttl)
413 struct ip_header *nh = packet->l3;
415 if (nh->ip_src != src) {
416 packet_set_ipv4_addr(packet, &nh->ip_src, src);
419 if (nh->ip_dst != dst) {
420 packet_set_ipv4_addr(packet, &nh->ip_dst, dst);
423 if (nh->ip_tos != tos) {
424 uint8_t *field = &nh->ip_tos;
426 nh->ip_csum = recalc_csum16(nh->ip_csum, htons((uint16_t) *field),
427 htons((uint16_t) tos));
431 if (nh->ip_ttl != ttl) {
432 uint8_t *field = &nh->ip_ttl;
434 nh->ip_csum = recalc_csum16(nh->ip_csum, htons(*field << 8),
441 packet_set_port(ovs_be16 *port, ovs_be16 new_port, ovs_be16 *csum)
443 if (*port != new_port) {
444 *csum = recalc_csum16(*csum, *port, new_port);
449 /* Sets the TCP source and destination port ('src' and 'dst' respectively) of
450 * the TCP header contained in 'packet'. 'packet' must be a valid TCP packet
451 * with its l4 marker properly populated. */
453 packet_set_tcp_port(struct ofpbuf *packet, ovs_be16 src, ovs_be16 dst)
455 struct tcp_header *th = packet->l4;
457 packet_set_port(&th->tcp_src, src, &th->tcp_csum);
458 packet_set_port(&th->tcp_dst, dst, &th->tcp_csum);
461 /* Sets the UDP source and destination port ('src' and 'dst' respectively) of
462 * the UDP header contained in 'packet'. 'packet' must be a valid UDP packet
463 * with its l4 marker properly populated. */
465 packet_set_udp_port(struct ofpbuf *packet, ovs_be16 src, ovs_be16 dst)
467 struct udp_header *uh = packet->l4;
470 packet_set_port(&uh->udp_src, src, &uh->udp_csum);
471 packet_set_port(&uh->udp_dst, dst, &uh->udp_csum);
474 uh->udp_csum = htons(0xffff);