/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 Isilon Systems, LLC.
* Copyright (c) 2005-2014 Sandvine Incorporated. All rights reserved.
* Copyright (c) 2000 Darrell Anderson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <machine/in_cksum.h>
#include <machine/pcb.h>
#include <net/debugnet.h>
#define DEBUGNET_INTERNAL
#include <net/debugnet_int.h>
int debugnet_arp_nretries = 3;
SYSCTL_INT(_net_debugnet, OID_AUTO, arp_nretries, CTLFLAG_RWTUN,
&debugnet_arp_nretries, 0,
"Number of ARP attempts before giving up");
/*
* Handler for IP packets: checks their sanity and then processes any debugnet
* ACK packets it finds.
*
* It needs to partially replicate the behaviour of ip_input() and udp_input().
*
* Parameters:
* pcb a pointer to the live debugnet PCB
* mb a pointer to an mbuf * containing the packet received
* Updates *mb if m_pullup et al change the pointer
* Assumes the calling function will take care of freeing the mbuf
*/
void
debugnet_handle_ip(struct debugnet_pcb *pcb, struct mbuf **mb)
{
struct ip *ip;
struct mbuf *m;
unsigned short hlen;
/* IP processing. */
m = *mb;
if (m->m_pkthdr.len < sizeof(struct ip)) {
DNETDEBUG("dropping packet too small for IP header\n");
return;
}
if (m->m_len < sizeof(struct ip)) {
m = m_pullup(m, sizeof(struct ip));
*mb = m;
if (m == NULL) {
DNETDEBUG("m_pullup failed\n");
return;
}
}
ip = mtod(m, struct ip *);
/* IP version. */
if (ip->ip_v != IPVERSION) {
DNETDEBUG("bad IP version %d\n", ip->ip_v);
return;
}
/* Header length. */
hlen = ip->ip_hl << 2;
if (hlen < sizeof(struct ip)) {
DNETDEBUG("bad IP header length (%hu)\n", hlen);
return;
}
if (hlen > m->m_len) {
m = m_pullup(m, hlen);
*mb = m;
if (m == NULL) {
DNETDEBUG("m_pullup failed\n");
return;
}
ip = mtod(m, struct ip *);
}
/* Ignore packets with IP options. */
if (hlen > sizeof(struct ip)) {
DNETDEBUG("drop packet with IP options\n");
return;
}
#ifdef INVARIANTS
if ((IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) &&
(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
DNETDEBUG("Bad IP header (RFC1122)\n");
return;
}
#endif
/* Checksum. */
if ((m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) != 0) {
if ((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0) {
DNETDEBUG("bad IP checksum\n");
return;
}
} else {
/* XXX */ ;
}
/* Convert fields to host byte order. */
ip->ip_len = ntohs(ip->ip_len);
if (ip->ip_len < hlen) {
DNETDEBUG("IP packet smaller (%hu) than header (%hu)\n",
ip->ip_len, hlen);
return;
}
if (m->m_pkthdr.len < ip->ip_len) {
DNETDEBUG("IP packet bigger (%hu) than ethernet packet (%d)\n",
ip->ip_len, m->m_pkthdr.len);
return;
}
if (m->m_pkthdr.len > ip->ip_len) {
/* Truncate the packet to the IP length. */
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip->ip_len;
m->m_pkthdr.len = ip->ip_len;
} else
m_adj(m, ip->ip_len - m->m_pkthdr.len);
}
ip->ip_off = ntohs(ip->ip_off);
/* Check that the source is the server's IP. */
if (ip->ip_src.s_addr != pcb->dp_server) {
DNETDEBUG("drop packet not from server (from 0x%x)\n",
ip->ip_src.s_addr);
return;
}
/* Check if the destination IP is ours. */
if (ip->ip_dst.s_addr != pcb->dp_client) {
DNETDEBUGV("drop packet not to our IP\n");
return;
}
if (ip->ip_p != IPPROTO_UDP) {
DNETDEBUG("drop non-UDP packet\n");
return;
}
/* Do not deal with fragments. */
if ((ip->ip_off & (IP_MF | IP_OFFMASK)) != 0) {
DNETDEBUG("drop fragmented packet\n");
return;
}
if ((m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) != 0) {
if ((m->m_pkthdr.csum_flags & CSUM_DATA_VALID) == 0) {
DNETDEBUG("bad UDP checksum\n");
return;
}
} else {
/* XXX */ ;
}
/* UDP custom is to have packet length not include IP header. */
ip->ip_len -= hlen;
/* Checked above before decoding IP header. */
MPASS(m->m_pkthdr.len >= sizeof(struct ipovly));
/* Put the UDP header at start of chain. */
m_adj(m, sizeof(struct ipovly));
debugnet_handle_udp(pcb, mb);
}
/*
* Builds and sends a single ARP request to locate the L2 address for a given
* INET address.
*
* Return value:
* 0 on success
* errno on error
*/
static int
debugnet_send_arp(struct debugnet_pcb *pcb, in_addr_t dst)
{
struct ether_addr bcast;
struct arphdr *ah;
struct ifnet *ifp;
struct mbuf *m;
int pktlen;
ifp = pcb->dp_ifp;
/* Fill-up a broadcast address. */
memset(&bcast, 0xFF, ETHER_ADDR_LEN);
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL) {
printf("%s: Out of mbufs\n", __func__);
return (ENOBUFS);
}
pktlen = arphdr_len2(ETHER_ADDR_LEN, sizeof(struct in_addr));
m->m_len = pktlen;
m->m_pkthdr.len = pktlen;
MH_ALIGN(m, pktlen);
ah = mtod(m, struct arphdr *);
ah->ar_hrd = htons(ARPHRD_ETHER);
ah->ar_pro = htons(ETHERTYPE_IP);
ah->ar_hln = ETHER_ADDR_LEN;
ah->ar_pln = sizeof(struct in_addr);
ah->ar_op = htons(ARPOP_REQUEST);
memcpy(ar_sha(ah), IF_LLADDR(ifp), ETHER_ADDR_LEN);
((struct in_addr *)ar_spa(ah))->s_addr = pcb->dp_client;
bzero(ar_tha(ah), ETHER_ADDR_LEN);
((struct in_addr *)ar_tpa(ah))->s_addr = dst;
return (debugnet_ether_output(m, ifp, bcast, ETHERTYPE_ARP));
}
/*
* Handler for ARP packets: checks their sanity and then
* 1. If the ARP is a request for our IP, respond with our MAC address
* 2. If the ARP is a response from our server, record its MAC address
*
* It needs to replicate partially the behaviour of arpintr() and
* in_arpinput().
*
* Parameters:
* pcb a pointer to the live debugnet PCB
* mb a pointer to an mbuf * containing the packet received
* Updates *mb if m_pullup et al change the pointer
* Assumes the calling function will take care of freeing the mbuf
*/
void
debugnet_handle_arp(struct debugnet_pcb *pcb, struct mbuf **mb)
{
char buf[INET_ADDRSTRLEN];
struct in_addr isaddr, itaddr;
struct ether_addr dst;
struct mbuf *m;
struct arphdr *ah;
struct ifnet *ifp;
uint8_t *enaddr;
int req_len, op;
m = *mb;
ifp = m->m_pkthdr.rcvif;
if (m->m_len < sizeof(struct arphdr)) {
m = m_pullup(m, sizeof(struct arphdr));
*mb = m;
if (m == NULL) {
DNETDEBUG("runt packet: m_pullup failed\n");
return;
}
}
ah = mtod(m, struct arphdr *);
if (ntohs(ah->ar_hrd) != ARPHRD_ETHER) {
DNETDEBUG("unknown hardware address 0x%2D)\n",
(unsigned char *)&ah->ar_hrd, "");
return;
}
if (ntohs(ah->ar_pro) != ETHERTYPE_IP) {
DNETDEBUG("drop ARP for unknown protocol %d\n",
ntohs(ah->ar_pro));
return;
}
req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
if (m->m_len < req_len) {
m = m_pullup(m, req_len);
*mb = m;
if (m == NULL) {
DNETDEBUG("runt packet: m_pullup failed\n");
return;
}
}
ah = mtod(m, struct arphdr *);
op = ntohs(ah->ar_op);
memcpy(&isaddr, ar_spa(ah), sizeof(isaddr));
memcpy(&itaddr, ar_tpa(ah), sizeof(itaddr));
enaddr = (uint8_t *)IF_LLADDR(ifp);
if (memcmp(ar_sha(ah), enaddr, ifp->if_addrlen) == 0) {
DNETDEBUG("ignoring ARP from myself\n");
return;
}
if (isaddr.s_addr == pcb->dp_client) {
printf("%s: %*D is using my IP address %s!\n", __func__,
ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
inet_ntoa_r(isaddr, buf));
return;
}
if (memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen) == 0) {
DNETDEBUG("ignoring ARP from broadcast address\n");
return;
}
if (op == ARPOP_REPLY) {
if (isaddr.s_addr != pcb->dp_gateway &&
isaddr.s_addr != pcb->dp_server) {
inet_ntoa_r(isaddr, buf);
DNETDEBUG("ignoring ARP reply from %s (not configured"
" server or gateway)\n", buf);
return;
}
memcpy(pcb->dp_gw_mac.octet, ar_sha(ah),
min(ah->ar_hln, ETHER_ADDR_LEN));
DNETDEBUG("got server MAC address %6D\n",
pcb->dp_gw_mac.octet, ":");
MPASS(pcb->dp_state == DN_STATE_INIT);
pcb->dp_state = DN_STATE_HAVE_GW_MAC;
return;
}
if (op != ARPOP_REQUEST) {
DNETDEBUG("ignoring ARP non-request/reply\n");
return;
}
if (itaddr.s_addr != pcb->dp_client) {
DNETDEBUG("ignoring ARP not to our IP\n");
return;
}
memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
memcpy(ar_sha(ah), enaddr, ah->ar_hln);
memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
ah->ar_op = htons(ARPOP_REPLY);
ah->ar_pro = htons(ETHERTYPE_IP);
m->m_flags &= ~(M_BCAST|M_MCAST);
m->m_len = arphdr_len(ah);
m->m_pkthdr.len = m->m_len;
memcpy(dst.octet, ar_tha(ah), ETHER_ADDR_LEN);
debugnet_ether_output(m, ifp, dst, ETHERTYPE_ARP);
*mb = NULL;
}
/*
* Sends ARP requests to locate the server and waits for a response.
* We first try to ARP the server itself, and fall back to the provided
* gateway if the server appears to be off-link.
*
* Return value:
* 0 on success
* errno on error
*/
int
debugnet_arp_gw(struct debugnet_pcb *pcb)
{
in_addr_t dst;
int error, polls, retries;
dst = pcb->dp_server;
restart:
for (retries = 0; retries < debugnet_arp_nretries; retries++) {
error = debugnet_send_arp(pcb, dst);
if (error != 0)
return (error);
for (polls = 0; polls < debugnet_npolls &&
pcb->dp_state < DN_STATE_HAVE_GW_MAC; polls++) {
debugnet_network_poll(pcb);
DELAY(500);
}
if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
break;
printf("(ARP retry)");
}
if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
return (0);
if (dst == pcb->dp_server) {
printf("\nFailed to ARP server");
if (pcb->dp_gateway != INADDR_ANY) {
printf(", trying to reach gateway...\n");
dst = pcb->dp_gateway;
goto restart;
} else
printf(".\n");
} else
printf("\nFailed to ARP gateway.\n");
return (ETIMEDOUT);
}
/*
* Unreliable IPv4 transmission of an mbuf chain to the debugnet server
* Note: can't handle fragmentation; fails if the packet is larger than
* ifp->if_mtu after adding the UDP/IP headers
*
* Parameters:
* pcb The debugnet context block
* m mbuf chain
*
* Returns:
* int see errno.h, 0 for success
*/
int
debugnet_ip_output(struct debugnet_pcb *pcb, struct mbuf *m)
{
struct udphdr *udp;
struct ifnet *ifp;
struct ip *ip;
MPASS(pcb->dp_state >= DN_STATE_HAVE_GW_MAC);
ifp = pcb->dp_ifp;
M_PREPEND(m, sizeof(*ip), M_NOWAIT);
if (m == NULL) {
printf("%s: out of mbufs\n", __func__);
return (ENOBUFS);
}
if (m->m_pkthdr.len > ifp->if_mtu) {
printf("%s: Packet is too big: %d > MTU %u\n", __func__,
m->m_pkthdr.len, ifp->if_mtu);
m_freem(m);
return (ENOBUFS);
}
ip = mtod(m, void *);
udp = (void *)(ip + 1);
memset(ip, 0, offsetof(struct ip, ip_p));
ip->ip_p = IPPROTO_UDP;
ip->ip_sum = udp->uh_ulen;
ip->ip_src = (struct in_addr) { pcb->dp_client };
ip->ip_dst = (struct in_addr) { pcb->dp_server };
/* Compute UDP-IPv4 checksum. */
udp->uh_sum = in_cksum(m, m->m_pkthdr.len);
if (udp->uh_sum == 0)
udp->uh_sum = 0xffff;
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(*ip) >> 2;
ip->ip_tos = 0;
ip->ip_len = htons(m->m_pkthdr.len);
ip->ip_id = 0;
ip->ip_off = htons(IP_DF);
ip->ip_ttl = 255;
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, sizeof(struct ip));
return (debugnet_ether_output(m, ifp, pcb->dp_gw_mac, ETHERTYPE_IP));
}
