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)
89 if (pcb->dp_state < DN_STATE_HAVE_GW_MAC)
94 if (m->m_pkthdr.len < sizeof(struct ip)) {
95 DNETDEBUG("dropping packet too small for IP header\n");
98 if (m->m_len < sizeof(struct ip)) {
99 m = m_pullup(m, sizeof(struct ip));
102 DNETDEBUG("m_pullup failed\n");
106 ip = mtod(m, struct ip *);
109 if (ip->ip_v != IPVERSION) {
110 DNETDEBUG("bad IP version %d\n", ip->ip_v);
115 hlen = ip->ip_hl << 2;
116 if (hlen < sizeof(struct ip)) {
117 DNETDEBUG("bad IP header length (%hu)\n", hlen);
120 if (hlen > m->m_len) {
121 m = m_pullup(m, hlen);
124 DNETDEBUG("m_pullup failed\n");
127 ip = mtod(m, struct ip *);
129 /* Ignore packets with IP options. */
130 if (hlen > sizeof(struct ip)) {
131 DNETDEBUG("drop packet with IP options\n");
136 if ((IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
137 IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) &&
138 (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
139 DNETDEBUG("Bad IP header (RFC1122)\n");
145 if ((m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) != 0) {
146 if ((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0) {
147 DNETDEBUG("bad IP checksum\n");
154 /* Convert fields to host byte order. */
155 ip->ip_len = ntohs(ip->ip_len);
156 if (ip->ip_len < hlen) {
157 DNETDEBUG("IP packet smaller (%hu) than header (%hu)\n",
161 if (m->m_pkthdr.len < ip->ip_len) {
162 DNETDEBUG("IP packet bigger (%hu) than ethernet packet (%d)\n",
163 ip->ip_len, m->m_pkthdr.len);
166 if (m->m_pkthdr.len > ip->ip_len) {
167 /* Truncate the packet to the IP length. */
168 if (m->m_len == m->m_pkthdr.len) {
169 m->m_len = ip->ip_len;
170 m->m_pkthdr.len = ip->ip_len;
172 m_adj(m, ip->ip_len - m->m_pkthdr.len);
175 ip->ip_off = ntohs(ip->ip_off);
177 /* Check that the source is the server's IP. */
178 if (ip->ip_src.s_addr != pcb->dp_server) {
179 DNETDEBUG("drop packet not from server (from 0x%x)\n",
184 /* Check if the destination IP is ours. */
185 if (ip->ip_dst.s_addr != pcb->dp_client) {
186 DNETDEBUGV("drop packet not to our IP\n");
190 if (ip->ip_p != IPPROTO_UDP) {
191 DNETDEBUG("drop non-UDP packet\n");
195 /* Do not deal with fragments. */
196 if ((ip->ip_off & (IP_MF | IP_OFFMASK)) != 0) {
197 DNETDEBUG("drop fragmented packet\n");
201 if ((m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) != 0) {
202 if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID) == 0) {
203 DNETDEBUG("bad UDP checksum\n");
210 /* UDP custom is to have packet length not include IP header. */
213 /* Checked above before decoding IP header. */
214 MPASS(m->m_pkthdr.len >= sizeof(struct ipovly));
216 /* Put the UDP header at start of chain. */
217 m_adj(m, sizeof(struct ipovly));
218 debugnet_handle_udp(pcb, mb);
222 * Builds and sends a single ARP request to locate the L2 address for a given
230 debugnet_send_arp(struct debugnet_pcb *pcb, in_addr_t dst)
232 struct ether_addr bcast;
240 /* Fill-up a broadcast address. */
241 memset(&bcast, 0xFF, ETHER_ADDR_LEN);
242 m = m_gethdr(M_NOWAIT, MT_DATA);
244 printf("%s: Out of mbufs\n", __func__);
247 pktlen = arphdr_len2(ETHER_ADDR_LEN, sizeof(struct in_addr));
249 m->m_pkthdr.len = pktlen;
251 ah = mtod(m, struct arphdr *);
252 ah->ar_hrd = htons(ARPHRD_ETHER);
253 ah->ar_pro = htons(ETHERTYPE_IP);
254 ah->ar_hln = ETHER_ADDR_LEN;
255 ah->ar_pln = sizeof(struct in_addr);
256 ah->ar_op = htons(ARPOP_REQUEST);
257 memcpy(ar_sha(ah), IF_LLADDR(ifp), ETHER_ADDR_LEN);
258 ((struct in_addr *)ar_spa(ah))->s_addr = pcb->dp_client;
259 bzero(ar_tha(ah), ETHER_ADDR_LEN);
260 ((struct in_addr *)ar_tpa(ah))->s_addr = dst;
261 return (debugnet_ether_output(m, ifp, bcast, ETHERTYPE_ARP));
265 * Handler for ARP packets: checks their sanity and then
266 * 1. If the ARP is a request for our IP, respond with our MAC address
267 * 2. If the ARP is a response from our server, record its MAC address
269 * It needs to replicate partially the behaviour of arpintr() and
273 * pcb a pointer to the live debugnet PCB
274 * mb a pointer to an mbuf * containing the packet received
275 * Updates *mb if m_pullup et al change the pointer
276 * Assumes the calling function will take care of freeing the mbuf
279 debugnet_handle_arp(struct debugnet_pcb *pcb, struct mbuf **mb)
281 char buf[INET_ADDRSTRLEN];
282 struct in_addr isaddr, itaddr;
283 struct ether_addr dst;
291 ifp = m->m_pkthdr.rcvif;
292 if (m->m_len < sizeof(struct arphdr)) {
293 m = m_pullup(m, sizeof(struct arphdr));
296 DNETDEBUG("runt packet: m_pullup failed\n");
301 ah = mtod(m, struct arphdr *);
302 if (ntohs(ah->ar_hrd) != ARPHRD_ETHER) {
303 DNETDEBUG("unknown hardware address 0x%2D)\n",
304 (unsigned char *)&ah->ar_hrd, "");
307 if (ntohs(ah->ar_pro) != ETHERTYPE_IP) {
308 DNETDEBUG("drop ARP for unknown protocol %d\n",
312 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
313 if (m->m_len < req_len) {
314 m = m_pullup(m, req_len);
317 DNETDEBUG("runt packet: m_pullup failed\n");
321 ah = mtod(m, struct arphdr *);
323 op = ntohs(ah->ar_op);
324 memcpy(&isaddr, ar_spa(ah), sizeof(isaddr));
325 memcpy(&itaddr, ar_tpa(ah), sizeof(itaddr));
326 enaddr = (uint8_t *)IF_LLADDR(ifp);
328 if (memcmp(ar_sha(ah), enaddr, ifp->if_addrlen) == 0) {
329 DNETDEBUG("ignoring ARP from myself\n");
333 if (isaddr.s_addr == pcb->dp_client) {
334 printf("%s: %*D is using my IP address %s!\n", __func__,
335 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
336 inet_ntoa_r(isaddr, buf));
340 if (memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen) == 0) {
341 DNETDEBUG("ignoring ARP from broadcast address\n");
345 if (op == ARPOP_REPLY) {
346 if (isaddr.s_addr != pcb->dp_gateway &&
347 isaddr.s_addr != pcb->dp_server) {
348 inet_ntoa_r(isaddr, buf);
349 DNETDEBUG("ignoring ARP reply from %s (not configured"
350 " server or gateway)\n", buf);
353 if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC) {
354 inet_ntoa_r(isaddr, buf);
355 DNETDEBUG("ignoring server ARP reply from %s (already"
356 " have gateway address)\n", buf);
359 MPASS(pcb->dp_state == DN_STATE_INIT);
360 memcpy(pcb->dp_gw_mac.octet, ar_sha(ah),
361 min(ah->ar_hln, ETHER_ADDR_LEN));
363 DNETDEBUG("got server MAC address %6D\n",
364 pcb->dp_gw_mac.octet, ":");
366 pcb->dp_state = DN_STATE_HAVE_GW_MAC;
370 if (op != ARPOP_REQUEST) {
371 DNETDEBUG("ignoring ARP non-request/reply\n");
375 if (itaddr.s_addr != pcb->dp_client) {
376 DNETDEBUG("ignoring ARP not to our IP\n");
380 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
381 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
382 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
383 memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
384 ah->ar_op = htons(ARPOP_REPLY);
385 ah->ar_pro = htons(ETHERTYPE_IP);
386 m->m_flags &= ~(M_BCAST|M_MCAST);
387 m->m_len = arphdr_len(ah);
388 m->m_pkthdr.len = m->m_len;
390 memcpy(dst.octet, ar_tha(ah), ETHER_ADDR_LEN);
391 debugnet_ether_output(m, ifp, dst, ETHERTYPE_ARP);
396 * Sends ARP requests to locate the server and waits for a response.
397 * We first try to ARP the server itself, and fall back to the provided
398 * gateway if the server appears to be off-link.
405 debugnet_arp_gw(struct debugnet_pcb *pcb)
408 int error, polls, retries;
410 dst = pcb->dp_server;
412 for (retries = 0; retries < debugnet_arp_nretries; retries++) {
413 error = debugnet_send_arp(pcb, dst);
416 for (polls = 0; polls < debugnet_npolls &&
417 pcb->dp_state < DN_STATE_HAVE_GW_MAC; polls++) {
418 debugnet_network_poll(pcb);
421 if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
423 printf("(ARP retry)");
425 if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
427 if (dst == pcb->dp_server) {
428 printf("\nFailed to ARP server");
429 if (pcb->dp_gateway != INADDR_ANY) {
430 printf(", trying to reach gateway...\n");
431 dst = pcb->dp_gateway;
436 printf("\nFailed to ARP gateway.\n");
442 * Unreliable IPv4 transmission of an mbuf chain to the debugnet server
443 * Note: can't handle fragmentation; fails if the packet is larger than
444 * ifp->if_mtu after adding the UDP/IP headers
447 * pcb The debugnet context block
451 * int see errno.h, 0 for success
454 debugnet_ip_output(struct debugnet_pcb *pcb, struct mbuf *m)
460 MPASS(pcb->dp_state >= DN_STATE_HAVE_GW_MAC);
464 M_PREPEND(m, sizeof(*ip), M_NOWAIT);
466 printf("%s: out of mbufs\n", __func__);
470 if (m->m_pkthdr.len > ifp->if_mtu) {
471 printf("%s: Packet is too big: %d > MTU %u\n", __func__,
472 m->m_pkthdr.len, ifp->if_mtu);
477 ip = mtod(m, void *);
478 udp = (void *)(ip + 1);
480 memset(ip, 0, offsetof(struct ip, ip_p));
481 ip->ip_p = IPPROTO_UDP;
482 ip->ip_sum = udp->uh_ulen;
483 ip->ip_src = (struct in_addr) { pcb->dp_client };
484 ip->ip_dst = (struct in_addr) { pcb->dp_server };
486 /* Compute UDP-IPv4 checksum. */
487 udp->uh_sum = in_cksum(m, m->m_pkthdr.len);
488 if (udp->uh_sum == 0)
489 udp->uh_sum = 0xffff;
491 ip->ip_v = IPVERSION;
492 ip->ip_hl = sizeof(*ip) >> 2;
494 ip->ip_len = htons(m->m_pkthdr.len);
496 ip->ip_off = htons(IP_DF);
499 ip->ip_sum = in_cksum(m, sizeof(struct ip));
501 return (debugnet_ether_output(m, ifp, pcb->dp_gw_mac, ETHERTYPE_IP));