diff options
Diffstat (limited to 'slirp/src/ip_icmp.c')
| -rw-r--r-- | slirp/src/ip_icmp.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/slirp/src/ip_icmp.c b/slirp/src/ip_icmp.c new file mode 100644 index 0000000000..120108f582 --- /dev/null +++ b/slirp/src/ip_icmp.c @@ -0,0 +1,469 @@ +/* + * Copyright (c) 1982, 1986, 1988, 1993 + * The Regents of the University of California. 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. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. + * + * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 + * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp + */ + +#include "slirp.h" +#include "ip_icmp.h" + +#ifndef WITH_ICMP_ERROR_MSG +#define WITH_ICMP_ERROR_MSG 0 +#endif + +/* The message sent when emulating PING */ +/* Be nice and tell them it's just a pseudo-ping packet */ +static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n"; + +/* list of actions for icmp_send_error() on RX of an icmp message */ +static const int icmp_flush[19] = { +/* ECHO REPLY (0) */ 0, + 1, + 1, +/* DEST UNREACH (3) */ 1, +/* SOURCE QUENCH (4)*/ 1, +/* REDIRECT (5) */ 1, + 1, + 1, +/* ECHO (8) */ 0, +/* ROUTERADVERT (9) */ 1, +/* ROUTERSOLICIT (10) */ 1, +/* TIME EXCEEDED (11) */ 1, +/* PARAMETER PROBLEM (12) */ 1, +/* TIMESTAMP (13) */ 0, +/* TIMESTAMP REPLY (14) */ 0, +/* INFO (15) */ 0, +/* INFO REPLY (16) */ 0, +/* ADDR MASK (17) */ 0, +/* ADDR MASK REPLY (18) */ 0 +}; + +void icmp_init(Slirp *slirp) +{ + slirp->icmp.so_next = slirp->icmp.so_prev = &slirp->icmp; + slirp->icmp_last_so = &slirp->icmp; +} + +void icmp_cleanup(Slirp *slirp) +{ + while (slirp->icmp.so_next != &slirp->icmp) { + icmp_detach(slirp->icmp.so_next); + } +} + +static int icmp_send(struct socket *so, struct mbuf *m, int hlen) +{ + struct ip *ip = mtod(m, struct ip *); + struct sockaddr_in addr; + + so->s = slirp_socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP); + if (so->s == -1) { + return -1; + } + + so->so_m = m; + so->so_faddr = ip->ip_dst; + so->so_laddr = ip->ip_src; + so->so_iptos = ip->ip_tos; + so->so_type = IPPROTO_ICMP; + so->so_state = SS_ISFCONNECTED; + so->so_expire = curtime + SO_EXPIRE; + + addr.sin_family = AF_INET; + addr.sin_addr = so->so_faddr; + + insque(so, &so->slirp->icmp); + + if (sendto(so->s, m->m_data + hlen, m->m_len - hlen, 0, + (struct sockaddr *)&addr, sizeof(addr)) == -1) { + DEBUG_MISC("icmp_input icmp sendto tx errno = %d-%s", + errno, strerror(errno)); + icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno)); + icmp_detach(so); + } + + return 0; +} + +void icmp_detach(struct socket *so) +{ + so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque); + closesocket(so->s); + sofree(so); +} + +/* + * Process a received ICMP message. + */ +void +icmp_input(struct mbuf *m, int hlen) +{ + register struct icmp *icp; + register struct ip *ip=mtod(m, struct ip *); + int icmplen=ip->ip_len; + Slirp *slirp = m->slirp; + + DEBUG_CALL("icmp_input"); + DEBUG_ARG("m = %p", m); + DEBUG_ARG("m_len = %d", m->m_len); + + /* + * Locate icmp structure in mbuf, and check + * that its not corrupted and of at least minimum length. + */ + if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */ + freeit: + m_free(m); + goto end_error; + } + + m->m_len -= hlen; + m->m_data += hlen; + icp = mtod(m, struct icmp *); + if (cksum(m, icmplen)) { + goto freeit; + } + m->m_len += hlen; + m->m_data -= hlen; + + DEBUG_ARG("icmp_type = %d", icp->icmp_type); + switch (icp->icmp_type) { + case ICMP_ECHO: + ip->ip_len += hlen; /* since ip_input subtracts this */ + if (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr || + ip->ip_dst.s_addr == slirp->vnameserver_addr.s_addr) { + icmp_reflect(m); + } else if (slirp->restricted) { + goto freeit; + } else { + struct socket *so; + struct sockaddr_storage addr; + so = socreate(slirp); + if (icmp_send(so, m, hlen) == 0) { + return; + } + if (udp_attach(so, AF_INET) == -1) { + DEBUG_MISC("icmp_input udp_attach errno = %d-%s", + errno,strerror(errno)); + sofree(so); + m_free(m); + goto end_error; + } + so->so_m = m; + so->so_ffamily = AF_INET; + so->so_faddr = ip->ip_dst; + so->so_fport = htons(7); + so->so_lfamily = AF_INET; + so->so_laddr = ip->ip_src; + so->so_lport = htons(9); + so->so_iptos = ip->ip_tos; + so->so_type = IPPROTO_ICMP; + so->so_state = SS_ISFCONNECTED; + + /* Send the packet */ + addr = so->fhost.ss; + sotranslate_out(so, &addr); + + if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0, + (struct sockaddr *)&addr, sockaddr_size(&addr)) == -1) { + DEBUG_MISC("icmp_input udp sendto tx errno = %d-%s", + errno,strerror(errno)); + icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno)); + udp_detach(so); + } + } /* if ip->ip_dst.s_addr == alias_addr.s_addr */ + break; + case ICMP_UNREACH: + /* XXX? report error? close socket? */ + case ICMP_TIMXCEED: + case ICMP_PARAMPROB: + case ICMP_SOURCEQUENCH: + case ICMP_TSTAMP: + case ICMP_MASKREQ: + case ICMP_REDIRECT: + m_free(m); + break; + + default: + m_free(m); + } /* swith */ + +end_error: + /* m is m_free()'d xor put in a socket xor or given to ip_send */ + return; +} + + +/* + * Send an ICMP message in response to a situation + * + * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do). + * MUST NOT change this header information. + * MUST NOT reply to a multicast/broadcast IP address. + * MUST NOT reply to a multicast/broadcast MAC address. + * MUST reply to only the first fragment. + */ +/* + * Send ICMP_UNREACH back to the source regarding msrc. + * mbuf *msrc is used as a template, but is NOT m_free()'d. + * It is reported as the bad ip packet. The header should + * be fully correct and in host byte order. + * ICMP fragmentation is illegal. All machines must accept 576 bytes in one + * packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548 + */ + +#define ICMP_MAXDATALEN (IP_MSS-28) +void +icmp_send_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize, + const char *message) +{ + unsigned hlen, shlen, s_ip_len; + register struct ip *ip; + register struct icmp *icp; + register struct mbuf *m; + + DEBUG_CALL("icmp_send_error"); + DEBUG_ARG("msrc = %p", msrc); + DEBUG_ARG("msrc_len = %d", msrc->m_len); + + if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error; + + /* check msrc */ + if(!msrc) goto end_error; + ip = mtod(msrc, struct ip *); + if (slirp_debug & DBG_MISC) { + char bufa[20], bufb[20]; + strcpy(bufa, inet_ntoa(ip->ip_src)); + strcpy(bufb, inet_ntoa(ip->ip_dst)); + DEBUG_MISC(" %.16s to %.16s", bufa, bufb); + } + if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */ + + /* Do not reply to source-only IPs */ + if ((ip->ip_src.s_addr & htonl(~(0xf << 28))) == 0) { + goto end_error; + } + + shlen=ip->ip_hl << 2; + s_ip_len=ip->ip_len; + if(ip->ip_p == IPPROTO_ICMP) { + icp = (struct icmp *)((char *)ip + shlen); + /* + * Assume any unknown ICMP type is an error. This isn't + * specified by the RFC, but think about it.. + */ + if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error; + } + + /* make a copy */ + m = m_get(msrc->slirp); + if (!m) { + goto end_error; + } + + { int new_m_size; + new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN; + if(new_m_size>m->m_size) m_inc(m, new_m_size); + } + memcpy(m->m_data, msrc->m_data, msrc->m_len); + m->m_len = msrc->m_len; /* copy msrc to m */ + + /* make the header of the reply packet */ + ip = mtod(m, struct ip *); + hlen= sizeof(struct ip ); /* no options in reply */ + + /* fill in icmp */ + m->m_data += hlen; + m->m_len -= hlen; + + icp = mtod(m, struct icmp *); + + if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */ + else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */ + s_ip_len=ICMP_MAXDATALEN; + + m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */ + + /* min. size = 8+sizeof(struct ip)+8 */ + + icp->icmp_type = type; + icp->icmp_code = code; + icp->icmp_id = 0; + icp->icmp_seq = 0; + + memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */ + HTONS(icp->icmp_ip.ip_len); + HTONS(icp->icmp_ip.ip_id); + HTONS(icp->icmp_ip.ip_off); + + if (message && WITH_ICMP_ERROR_MSG) { /* append message to ICMP packet */ + int message_len; + char *cpnt; + message_len=strlen(message); + if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN; + cpnt=(char *)m->m_data+m->m_len; + memcpy(cpnt, message, message_len); + m->m_len+=message_len; + } + + icp->icmp_cksum = 0; + icp->icmp_cksum = cksum(m, m->m_len); + + m->m_data -= hlen; + m->m_len += hlen; + + /* fill in ip */ + ip->ip_hl = hlen >> 2; + ip->ip_len = m->m_len; + + ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */ + + ip->ip_ttl = MAXTTL; + ip->ip_p = IPPROTO_ICMP; + ip->ip_dst = ip->ip_src; /* ip addresses */ + ip->ip_src = m->slirp->vhost_addr; + + (void ) ip_output((struct socket *)NULL, m); + +end_error: + return; +} +#undef ICMP_MAXDATALEN + +/* + * Reflect the ip packet back to the source + */ +void +icmp_reflect(struct mbuf *m) +{ + register struct ip *ip = mtod(m, struct ip *); + int hlen = ip->ip_hl << 2; + int optlen = hlen - sizeof(struct ip ); + register struct icmp *icp; + + /* + * Send an icmp packet back to the ip level, + * after supplying a checksum. + */ + m->m_data += hlen; + m->m_len -= hlen; + icp = mtod(m, struct icmp *); + + icp->icmp_type = ICMP_ECHOREPLY; + icp->icmp_cksum = 0; + icp->icmp_cksum = cksum(m, ip->ip_len - hlen); + + m->m_data -= hlen; + m->m_len += hlen; + + /* fill in ip */ + if (optlen > 0) { + /* + * Strip out original options by copying rest of first + * mbuf's data back, and adjust the IP length. + */ + memmove((char *)(ip + 1), (char *)ip + hlen, + (unsigned )(m->m_len - hlen)); + hlen -= optlen; + ip->ip_hl = hlen >> 2; + ip->ip_len -= optlen; + m->m_len -= optlen; + } + + ip->ip_ttl = MAXTTL; + { /* swap */ + struct in_addr icmp_dst; + icmp_dst = ip->ip_dst; + ip->ip_dst = ip->ip_src; + ip->ip_src = icmp_dst; + } + + (void ) ip_output((struct socket *)NULL, m); +} + +void icmp_receive(struct socket *so) +{ + struct mbuf *m = so->so_m; + struct ip *ip = mtod(m, struct ip *); + int hlen = ip->ip_hl << 2; + uint8_t error_code; + struct icmp *icp; + int id, len; + + m->m_data += hlen; + m->m_len -= hlen; + icp = mtod(m, struct icmp *); + + id = icp->icmp_id; + len = recv(so->s, icp, M_ROOM(m), 0); + /* + * The behavior of reading SOCK_DGRAM+IPPROTO_ICMP sockets is inconsistent + * between host OSes. On Linux, only the ICMP header and payload is + * included. On macOS/Darwin, the socket acts like a raw socket and + * includes the IP header as well. On other BSDs, SOCK_DGRAM+IPPROTO_ICMP + * sockets aren't supported at all, so we treat them like raw sockets. It + * isn't possible to detect this difference at runtime, so we must use an + * #ifdef to determine if we need to remove the IP header. + */ +#ifdef CONFIG_BSD + if (len >= sizeof(struct ip)) { + struct ip *inner_ip = mtod(m, struct ip *); + int inner_hlen = inner_ip->ip_hl << 2; + if (inner_hlen > len) { + len = -1; + errno = -EINVAL; + } else { + len -= inner_hlen; + memmove(icp, (unsigned char *)icp + inner_hlen, len); + } + } else { + len = -1; + errno = -EINVAL; + } +#endif + icp->icmp_id = id; + + m->m_data -= hlen; + m->m_len += hlen; + + if (len == -1 || len == 0) { + if (errno == ENETUNREACH) { + error_code = ICMP_UNREACH_NET; + } else { + error_code = ICMP_UNREACH_HOST; + } + DEBUG_MISC(" udp icmp rx errno = %d-%s", errno, + strerror(errno)); + icmp_send_error(so->so_m, ICMP_UNREACH, error_code, 0, strerror(errno)); + } else { + icmp_reflect(so->so_m); + so->so_m = NULL; /* Don't m_free() it again! */ + } + icmp_detach(so); +} |