2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2019 Isilon Systems, LLC.
5 * Copyright (c) 2005-2014 Sandvine Incorporated. All rights reserved.
6 * Copyright (c) 2000 Darrell Anderson
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/errno.h>
39 #include <sys/socket.h>
40 #include <sys/sysctl.h>
42 #include <net/ethernet.h>
44 #include <net/if_arp.h>
45 #include <net/if_dl.h>
46 #include <net/if_types.h>
47 #include <net/if_var.h>
49 #include <netinet/in.h>
50 #include <netinet/in_systm.h>
51 #include <netinet/in_var.h>
52 #include <netinet/ip.h>
53 #include <netinet/ip_var.h>
54 #include <netinet/ip_options.h>
55 #include <netinet/udp.h>
56 #include <netinet/udp_var.h>
58 #include <machine/in_cksum.h>
59 #include <machine/pcb.h>
61 #include <net/debugnet.h>
62 #define DEBUGNET_INTERNAL
63 #include <net/debugnet_int.h>
65 int debugnet_arp_nretries = 3;
66 SYSCTL_INT(_net_debugnet, OID_AUTO, arp_nretries, CTLFLAG_RWTUN,
67 &debugnet_arp_nretries, 0,
68 "Number of ARP attempts before giving up");
71 * Handler for IP packets: checks their sanity and then processes any debugnet
72 * ACK packets it finds.
74 * It needs to partially replicate the behaviour of ip_input() and udp_input().
77 * pcb a pointer to the live debugnet PCB
78 * mb a pointer to an mbuf * containing the packet received
79 * Updates *mb if m_pullup et al change the pointer
80 * Assumes the calling function will take care of freeing the mbuf
83 debugnet_handle_ip(struct debugnet_pcb *pcb, struct mbuf **mb)
91 if (m->m_pkthdr.len < sizeof(struct ip)) {
92 DNETDEBUG("dropping packet too small for IP header\n");
95 if (m->m_len < sizeof(struct ip)) {
96 m = m_pullup(m, sizeof(struct ip));
99 DNETDEBUG("m_pullup failed\n");
103 ip = mtod(m, struct ip *);
106 if (ip->ip_v != IPVERSION) {
107 DNETDEBUG("bad IP version %d\n", ip->ip_v);
112 hlen = ip->ip_hl << 2;
113 if (hlen < sizeof(struct ip)) {
114 DNETDEBUG("bad IP header length (%hu)\n", hlen);
117 if (hlen > m->m_len) {
118 m = m_pullup(m, hlen);
121 DNETDEBUG("m_pullup failed\n");
124 ip = mtod(m, struct ip *);
126 /* Ignore packets with IP options. */
127 if (hlen > sizeof(struct ip)) {
128 DNETDEBUG("drop packet with IP options\n");
133 if ((IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
134 IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) &&
135 (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
136 DNETDEBUG("Bad IP header (RFC1122)\n");
142 if ((m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) != 0) {
143 if ((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0) {
144 DNETDEBUG("bad IP checksum\n");
151 /* Convert fields to host byte order. */
152 ip->ip_len = ntohs(ip->ip_len);
153 if (ip->ip_len < hlen) {
154 DNETDEBUG("IP packet smaller (%hu) than header (%hu)\n",
158 if (m->m_pkthdr.len < ip->ip_len) {
159 DNETDEBUG("IP packet bigger (%hu) than ethernet packet (%d)\n",
160 ip->ip_len, m->m_pkthdr.len);
163 if (m->m_pkthdr.len > ip->ip_len) {
165 /* Truncate the packet to the IP length. */
166 if (m->m_len == m->m_pkthdr.len) {
167 m->m_len = ip->ip_len;
168 m->m_pkthdr.len = ip->ip_len;
170 m_adj(m, ip->ip_len - m->m_pkthdr.len);
173 ip->ip_off = ntohs(ip->ip_off);
175 /* Check that the source is the server's IP. */
176 if (ip->ip_src.s_addr != pcb->dp_server) {
177 DNETDEBUG("drop packet not from server (from 0x%x)\n",
182 /* Check if the destination IP is ours. */
183 if (ip->ip_dst.s_addr != pcb->dp_client) {
184 DNETDEBUGV("drop packet not to our IP\n");
188 if (ip->ip_p != IPPROTO_UDP) {
189 DNETDEBUG("drop non-UDP packet\n");
193 /* Do not deal with fragments. */
194 if ((ip->ip_off & (IP_MF | IP_OFFMASK)) != 0) {
195 DNETDEBUG("drop fragmented packet\n");
199 if ((m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) != 0) {
200 if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID) == 0) {
201 DNETDEBUG("bad UDP checksum\n");
208 /* UDP custom is to have packet length not include IP header. */
211 /* Checked above before decoding IP header. */
212 MPASS(m->m_pkthdr.len >= sizeof(struct ipovly));
214 /* Put the UDP header at start of chain. */
215 m_adj(m, sizeof(struct ipovly));
216 debugnet_handle_udp(pcb, mb);
220 * Builds and sends a single ARP request to locate the L2 address for a given
228 debugnet_send_arp(struct debugnet_pcb *pcb, in_addr_t dst)
230 struct ether_addr bcast;
238 /* Fill-up a broadcast address. */
239 memset(&bcast, 0xFF, ETHER_ADDR_LEN);
240 m = m_gethdr(M_NOWAIT, MT_DATA);
242 printf("%s: Out of mbufs\n", __func__);
245 pktlen = arphdr_len2(ETHER_ADDR_LEN, sizeof(struct in_addr));
247 m->m_pkthdr.len = pktlen;
249 ah = mtod(m, struct arphdr *);
250 ah->ar_hrd = htons(ARPHRD_ETHER);
251 ah->ar_pro = htons(ETHERTYPE_IP);
252 ah->ar_hln = ETHER_ADDR_LEN;
253 ah->ar_pln = sizeof(struct in_addr);
254 ah->ar_op = htons(ARPOP_REQUEST);
255 memcpy(ar_sha(ah), IF_LLADDR(ifp), ETHER_ADDR_LEN);
256 ((struct in_addr *)ar_spa(ah))->s_addr = pcb->dp_client;
257 bzero(ar_tha(ah), ETHER_ADDR_LEN);
258 ((struct in_addr *)ar_tpa(ah))->s_addr = dst;
259 return (debugnet_ether_output(m, ifp, bcast, ETHERTYPE_ARP));
263 * Handler for ARP packets: checks their sanity and then
264 * 1. If the ARP is a request for our IP, respond with our MAC address
265 * 2. If the ARP is a response from our server, record its MAC address
267 * It needs to replicate partially the behaviour of arpintr() and
271 * pcb a pointer to the live debugnet PCB
272 * mb a pointer to an mbuf * containing the packet received
273 * Updates *mb if m_pullup et al change the pointer
274 * Assumes the calling function will take care of freeing the mbuf
277 debugnet_handle_arp(struct debugnet_pcb *pcb, struct mbuf **mb)
279 char buf[INET_ADDRSTRLEN];
280 struct in_addr isaddr, itaddr;
281 struct ether_addr dst;
289 ifp = m->m_pkthdr.rcvif;
290 if (m->m_len < sizeof(struct arphdr)) {
291 m = m_pullup(m, sizeof(struct arphdr));
294 DNETDEBUG("runt packet: m_pullup failed\n");
299 ah = mtod(m, struct arphdr *);
300 if (ntohs(ah->ar_hrd) != ARPHRD_ETHER) {
301 DNETDEBUG("unknown hardware address 0x%2D)\n",
302 (unsigned char *)&ah->ar_hrd, "");
305 if (ntohs(ah->ar_pro) != ETHERTYPE_IP) {
306 DNETDEBUG("drop ARP for unknown protocol %d\n",
310 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
311 if (m->m_len < req_len) {
312 m = m_pullup(m, req_len);
315 DNETDEBUG("runt packet: m_pullup failed\n");
319 ah = mtod(m, struct arphdr *);
321 op = ntohs(ah->ar_op);
322 memcpy(&isaddr, ar_spa(ah), sizeof(isaddr));
323 memcpy(&itaddr, ar_tpa(ah), sizeof(itaddr));
324 enaddr = (uint8_t *)IF_LLADDR(ifp);
326 if (memcmp(ar_sha(ah), enaddr, ifp->if_addrlen) == 0) {
327 DNETDEBUG("ignoring ARP from myself\n");
331 if (isaddr.s_addr == pcb->dp_client) {
332 printf("%s: %*D is using my IP address %s!\n", __func__,
333 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
334 inet_ntoa_r(isaddr, buf));
338 if (memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen) == 0) {
339 DNETDEBUG("ignoring ARP from broadcast address\n");
343 if (op == ARPOP_REPLY) {
344 if (isaddr.s_addr != pcb->dp_gateway &&
345 isaddr.s_addr != pcb->dp_server) {
346 inet_ntoa_r(isaddr, buf);
347 DNETDEBUG("ignoring ARP reply from %s (not configured"
348 " server or gateway)\n", buf);
351 memcpy(pcb->dp_gw_mac.octet, ar_sha(ah),
352 min(ah->ar_hln, ETHER_ADDR_LEN));
354 DNETDEBUG("got server MAC address %6D\n",
355 pcb->dp_gw_mac.octet, ":");
357 MPASS(pcb->dp_state == DN_STATE_INIT);
358 pcb->dp_state = DN_STATE_HAVE_GW_MAC;
362 if (op != ARPOP_REQUEST) {
363 DNETDEBUG("ignoring ARP non-request/reply\n");
367 if (itaddr.s_addr != pcb->dp_client) {
368 DNETDEBUG("ignoring ARP not to our IP\n");
372 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
373 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
374 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
375 memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
376 ah->ar_op = htons(ARPOP_REPLY);
377 ah->ar_pro = htons(ETHERTYPE_IP);
378 m->m_flags &= ~(M_BCAST|M_MCAST);
379 m->m_len = arphdr_len(ah);
380 m->m_pkthdr.len = m->m_len;
382 memcpy(dst.octet, ar_tha(ah), ETHER_ADDR_LEN);
383 debugnet_ether_output(m, ifp, dst, ETHERTYPE_ARP);
388 * Sends ARP requests to locate the server and waits for a response.
389 * We first try to ARP the server itself, and fall back to the provided
390 * gateway if the server appears to be off-link.
397 debugnet_arp_gw(struct debugnet_pcb *pcb)
400 int error, polls, retries;
402 dst = pcb->dp_server;
404 for (retries = 0; retries < debugnet_arp_nretries; retries++) {
405 error = debugnet_send_arp(pcb, dst);
408 for (polls = 0; polls < debugnet_npolls &&
409 pcb->dp_state < DN_STATE_HAVE_GW_MAC; polls++) {
410 debugnet_network_poll(pcb);
413 if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
415 printf("(ARP retry)");
417 if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
419 if (dst == pcb->dp_server) {
420 printf("\nFailed to ARP server");
421 if (pcb->dp_gateway != INADDR_ANY) {
422 printf(", trying to reach gateway...\n");
423 dst = pcb->dp_gateway;
428 printf("\nFailed to ARP gateway.\n");
434 * Unreliable IPv4 transmission of an mbuf chain to the debugnet server
435 * Note: can't handle fragmentation; fails if the packet is larger than
436 * ifp->if_mtu after adding the UDP/IP headers
439 * pcb The debugnet context block
443 * int see errno.h, 0 for success
446 debugnet_ip_output(struct debugnet_pcb *pcb, struct mbuf *m)
452 MPASS(pcb->dp_state >= DN_STATE_HAVE_GW_MAC);
456 M_PREPEND(m, sizeof(*ip), M_NOWAIT);
458 printf("%s: out of mbufs\n", __func__);
462 if (m->m_pkthdr.len > ifp->if_mtu) {
463 printf("%s: Packet is too big: %d > MTU %u\n", __func__,
464 m->m_pkthdr.len, ifp->if_mtu);
469 ip = mtod(m, void *);
470 udp = (void *)(ip + 1);
472 memset(ip, 0, offsetof(struct ip, ip_p));
473 ip->ip_p = IPPROTO_UDP;
474 ip->ip_sum = udp->uh_ulen;
475 ip->ip_src = (struct in_addr) { pcb->dp_client };
476 ip->ip_dst = (struct in_addr) { pcb->dp_server };
478 /* Compute UDP-IPv4 checksum. */
479 udp->uh_sum = in_cksum(m, m->m_pkthdr.len);
480 if (udp->uh_sum == 0)
481 udp->uh_sum = 0xffff;
483 ip->ip_v = IPVERSION;
484 ip->ip_hl = sizeof(*ip) >> 2;
486 ip->ip_len = htons(m->m_pkthdr.len);
488 ip->ip_off = htons(IP_DF);
491 ip->ip_sum = in_cksum(m, sizeof(struct ip));
493 return (debugnet_ether_output(m, ifp, pcb->dp_gw_mac, ETHERTYPE_IP));