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qemu/libslirp/refs/heads/stable-4.9/./src/ip6_icmp.c
blob: ef6fb1f6deb8d1c68fc7515aba45b46c200661e3 [file]
/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (c) 2013
* Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
*/
#include "slirp.h"
#include "ip6_icmp.h"
#define NDP_Interval \
g_rand_int_range(slirp->grand, NDP_MinRtrAdvInterval, NDP_MaxRtrAdvInterval)
/* The message sent when emulating PING */
/* Be nice and tell them it's just a pseudo-ping packet */
static const char icmp6_ping_msg[] =
"This is a pseudo-PING packet used by Slirp to emulate ICMPV6 ECHO-REQUEST "
"packets.\n";
void icmp6_post_init(Slirp *slirp)
{
if (!slirp->in6_enabled) {
return;
}
slirp->ra_timer =
slirp_timer_new(slirp, SLIRP_TIMER_RA, NULL);
slirp->cb->timer_mod(slirp->ra_timer,
slirp->cb->clock_get_ns(slirp->opaque) / SCALE_MS +
NDP_Interval,
slirp->opaque);
}
void icmp6_cleanup(Slirp *slirp)
{
if (!slirp->in6_enabled) {
return;
}
slirp->cb->timer_free(slirp->ra_timer, slirp->opaque);
}
/* Send ICMP packet to the Internet, and save it to so_m */
static int icmp6_send(struct socket *so, struct mbuf *m, int hlen)
{
Slirp *slirp = m->slirp;
struct sockaddr_in6 addr;
/*
* 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.
*/
#if defined(BSD) && !defined(__GNU__)
so->so_type = IPPROTO_IPV6;
#else
so->so_type = IPPROTO_ICMPV6;
#endif
so->s = slirp_socket(AF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6);
if (not_valid_socket(so->s)) {
if (errno == EAFNOSUPPORT
|| errno == EPROTONOSUPPORT
|| errno == EACCES) {
/* Kernel doesn't support or allow ping sockets. */
so->so_type = IPPROTO_IPV6;
so->s = slirp_socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
}
}
if (not_valid_socket(so->s)) {
return -1;
}
slirp_register_poll_socket(so);
if (slirp_bind_outbound(so, AF_INET6) != 0) {
// bind failed - close socket
closesocket(so->s);
so->s = -1;
return -1;
}
M_DUP_DEBUG(slirp, m, 0, 0);
struct ip6 *ip = mtod(m, struct ip6 *);
so->so_m = m;
so->so_faddr6 = ip->ip_dst;
so->so_laddr6 = ip->ip_src;
so->so_state = SS_ISFCONNECTED;
so->so_expire = curtime + SO_EXPIRE;
addr.sin6_family = AF_INET6;
addr.sin6_addr = so->so_faddr6;
slirp_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("icmp6_input icmp sendto tx errno = %d-%s", errno,
g_strerror(errno));
icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
icmp_detach(so);
}
return 0;
}
static void icmp6_send_echoreply(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
struct icmp6 *icmp)
{
struct mbuf *t = m_get(slirp);
t->m_len = sizeof(struct ip6) + ntohs(ip->ip_pl);
memcpy(t->m_data, m->m_data, t->m_len);
/* IPv6 Packet */
struct ip6 *rip = mtod(t, struct ip6 *);
rip->ip_dst = ip->ip_src;
rip->ip_src = ip->ip_dst;
/* ICMPv6 packet */
t->m_data += sizeof(struct ip6);
struct icmp6 *ricmp = mtod(t, struct icmp6 *);
ricmp->icmp6_type = ICMP6_ECHO_REPLY;
ricmp->icmp6_cksum = 0;
/* Checksum */
t->m_data -= sizeof(struct ip6);
ricmp->icmp6_cksum = ip6_cksum(t);
ip6_output(NULL, t, 0);
}
void icmp6_forward_error(struct mbuf *m, uint8_t type, uint8_t code, struct in6_addr *src)
{
Slirp *slirp = m->slirp;
struct mbuf *t;
struct ip6 *ip = mtod(m, struct ip6 *);
char addrstr[INET6_ADDRSTRLEN];
DEBUG_CALL("icmp6_send_error");
DEBUG_ARG("type = %d, code = %d", type, code);
if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) || in6_zero(&ip->ip_src)) {
/* TODO icmp error? */
return;
}
t = m_get(slirp);
/* IPv6 packet */
struct ip6 *rip = mtod(t, struct ip6 *);
rip->ip_src = *src;
rip->ip_dst = ip->ip_src;
inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN);
DEBUG_ARG("target = %s", addrstr);
rip->ip_nh = IPPROTO_ICMPV6;
const int error_data_len = MIN(
m->m_len, slirp->if_mtu - (sizeof(struct ip6) + ICMP6_ERROR_MINLEN));
rip->ip_pl = htons(ICMP6_ERROR_MINLEN + error_data_len);
t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
/* ICMPv6 packet */
t->m_data += sizeof(struct ip6);
struct icmp6 *ricmp = mtod(t, struct icmp6 *);
ricmp->icmp6_type = type;
ricmp->icmp6_code = code;
ricmp->icmp6_cksum = 0;
switch (type) {
case ICMP6_UNREACH:
case ICMP6_TIMXCEED:
ricmp->icmp6_err.unused = 0;
break;
case ICMP6_TOOBIG:
ricmp->icmp6_err.mtu = htonl(slirp->if_mtu);
break;
case ICMP6_PARAMPROB:
/* TODO: Handle this case */
break;
default:
g_assert_not_reached();
}
t->m_data += ICMP6_ERROR_MINLEN;
memcpy(t->m_data, m->m_data, error_data_len);
/* Checksum */
t->m_data -= ICMP6_ERROR_MINLEN;
t->m_data -= sizeof(struct ip6);
ricmp->icmp6_cksum = ip6_cksum(t);
ip6_output(NULL, t, 0);
}
void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
{
struct in6_addr src = LINKLOCAL_ADDR;
icmp6_forward_error(m, type, code, &src);
}
/*
* Reflect the ip packet back to the source
*/
void icmp6_reflect(struct mbuf *m)
{
register struct ip6 *ip = mtod(m, struct ip6 *);
int hlen = sizeof(struct ip6);
register struct icmp6 *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 icmp6 *);
icp->icmp6_type = ICMP6_ECHO_REPLY;
m->m_data -= hlen;
m->m_len += hlen;
icp->icmp6_cksum = 0;
icp->icmp6_cksum = ip6_cksum(m);
ip->ip_hl = MAXTTL;
{ /* swap */
struct in6_addr icmp_dst;
icmp_dst = ip->ip_dst;
ip->ip_dst = ip->ip_src;
ip->ip_src = icmp_dst;
}
ip6_output((struct socket *)NULL, m, 0);
}
void icmp6_receive(struct socket *so)
{
struct mbuf *m = so->so_m;
struct ip6 *ip = mtod(m, struct ip6 *);
int hlen = sizeof(struct ip6);
uint8_t error_code;
struct icmp6 *icp;
int id, seq, len;
m->m_data += hlen;
m->m_len -= hlen;
icp = mtod(m, struct icmp6 *);
id = icp->icmp6_id;
seq = icp->icmp6_seq;
len = recv(so->s, icp, M_ROOM(m), 0);
icp->icmp6_id = id;
icp->icmp6_seq = seq;
m->m_data -= hlen;
m->m_len += hlen;
if (len == -1 || len == 0) {
if (errno == ENETUNREACH) {
error_code = ICMP6_UNREACH_NO_ROUTE;
} else {
error_code = ICMP6_UNREACH_ADDRESS;
}
DEBUG_MISC(" udp icmp rx errno = %d-%s", errno, g_strerror(errno));
icmp6_send_error(m, ICMP6_UNREACH, error_code);
} else {
m->m_len = hlen + len;
ip->ip_pl = htons(len);
icmp6_reflect(m);
so->so_m = NULL; /* Don't m_free() it again! */
}
icmp_detach(so);
}
/*
* Send NDP Router Advertisement
*/
static void ndp_send_ra(Slirp *slirp)
{
DEBUG_CALL("ndp_send_ra");
/* Build IPv6 packet */
struct mbuf *t = m_get(slirp);
struct ip6 *rip = mtod(t, struct ip6 *);
size_t pl_size = 0;
struct in6_addr addr;
uint16_t port;
uint32_t scope_id;
rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
rip->ip_nh = IPPROTO_ICMPV6;
/* Build ICMPv6 packet */
t->m_data += sizeof(struct ip6);
struct icmp6 *ricmp = mtod(t, struct icmp6 *);
ricmp->icmp6_type = ICMP6_NDP_RA;
ricmp->icmp6_code = 0;
ricmp->icmp6_cksum = 0;
/* NDP */
ricmp->icmp6_nra.chl = NDP_AdvCurHopLimit;
ricmp->icmp6_nra.M = NDP_AdvManagedFlag;
ricmp->icmp6_nra.O = NDP_AdvOtherConfigFlag;
ricmp->icmp6_nra.reserved = 0;
ricmp->icmp6_nra.lifetime = htons(NDP_AdvDefaultLifetime);
ricmp->icmp6_nra.reach_time = htonl(NDP_AdvReachableTime);
ricmp->icmp6_nra.retrans_time = htonl(NDP_AdvRetransTime);
t->m_data += ICMP6_NDP_RA_MINLEN;
pl_size += ICMP6_NDP_RA_MINLEN;
/* Source link-layer address (NDP option) */
struct ndpopt *opt = mtod(t, struct ndpopt *);
opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
in6_compute_ethaddr(rip->ip_src, opt->ndpopt_linklayer);
t->m_data += NDPOPT_LINKLAYER_LEN;
pl_size += NDPOPT_LINKLAYER_LEN;
/* Prefix information (NDP option) */
struct ndpopt *opt2 = mtod(t, struct ndpopt *);
opt2->ndpopt_type = NDPOPT_PREFIX_INFO;
opt2->ndpopt_len = NDPOPT_PREFIXINFO_LEN / 8;
opt2->ndpopt_prefixinfo.prefix_length = slirp->vprefix_len;
opt2->ndpopt_prefixinfo.L = 1;
opt2->ndpopt_prefixinfo.A = 1;
opt2->ndpopt_prefixinfo.reserved1 = 0;
opt2->ndpopt_prefixinfo.valid_lt = htonl(NDP_AdvValidLifetime);
opt2->ndpopt_prefixinfo.pref_lt = htonl(NDP_AdvPrefLifetime);
opt2->ndpopt_prefixinfo.reserved2 = 0;
opt2->ndpopt_prefixinfo.prefix = slirp->vprefix_addr6;
t->m_data += NDPOPT_PREFIXINFO_LEN;
pl_size += NDPOPT_PREFIXINFO_LEN;
/* Prefix information (NDP option) */
if (get_dns6_addr(&addr, &port, &scope_id) >= 0) {
/* Host system does have an IPv6 DNS server, announce our proxy. */
struct ndpopt *opt3 = mtod(t, struct ndpopt *);
opt3->ndpopt_type = NDPOPT_RDNSS;
opt3->ndpopt_len = NDPOPT_RDNSS_LEN / 8;
opt3->ndpopt_rdnss.reserved = 0;
opt3->ndpopt_rdnss.lifetime = htonl(2 * NDP_MaxRtrAdvInterval);
opt3->ndpopt_rdnss.addr = slirp->vnameserver_addr6;
t->m_data += NDPOPT_RDNSS_LEN;
pl_size += NDPOPT_RDNSS_LEN;
}
rip->ip_pl = htons(pl_size);
t->m_data -= sizeof(struct ip6) + pl_size;
t->m_len = sizeof(struct ip6) + pl_size;
/* ICMPv6 Checksum */
ricmp->icmp6_cksum = ip6_cksum(t);
ip6_output(NULL, t, 0);
}
void ra_timer_handler(Slirp *slirp, void *unused)
{
slirp->cb->timer_mod(slirp->ra_timer,
slirp->cb->clock_get_ns(slirp->opaque) / SCALE_MS +
NDP_Interval,
slirp->opaque);
ndp_send_ra(slirp);
}
/*
* Send NDP Neighbor Solitication
*/
void ndp_send_ns(Slirp *slirp, struct in6_addr addr)
{
char addrstr[INET6_ADDRSTRLEN];
inet_ntop(AF_INET6, &addr, addrstr, INET6_ADDRSTRLEN);
DEBUG_CALL("ndp_send_ns");
DEBUG_ARG("target = %s", addrstr);
/* Build IPv6 packet */
struct mbuf *t = m_get(slirp);
struct ip6 *rip = mtod(t, struct ip6 *);
rip->ip_src = slirp->vhost_addr6;
rip->ip_dst = (struct in6_addr)SOLICITED_NODE_PREFIX;
memcpy(&rip->ip_dst.s6_addr[13], &addr.s6_addr[13], 3);
rip->ip_nh = IPPROTO_ICMPV6;
rip->ip_pl = htons(ICMP6_NDP_NS_MINLEN + NDPOPT_LINKLAYER_LEN);
t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
/* Build ICMPv6 packet */
t->m_data += sizeof(struct ip6);
struct icmp6 *ricmp = mtod(t, struct icmp6 *);
ricmp->icmp6_type = ICMP6_NDP_NS;
ricmp->icmp6_code = 0;
ricmp->icmp6_cksum = 0;
/* NDP */
ricmp->icmp6_nns.reserved = 0;
ricmp->icmp6_nns.target = addr;
/* Build NDP option */
t->m_data += ICMP6_NDP_NS_MINLEN;
struct ndpopt *opt = mtod(t, struct ndpopt *);
opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
in6_compute_ethaddr(slirp->vhost_addr6, opt->ndpopt_linklayer);
/* ICMPv6 Checksum */
t->m_data -= ICMP6_NDP_NA_MINLEN;
t->m_data -= sizeof(struct ip6);
ricmp->icmp6_cksum = ip6_cksum(t);
ip6_output(NULL, t, 1);
}
/*
* Send NDP Neighbor Advertisement
*/
static void ndp_send_na(Slirp *slirp, struct ip6 *ip, struct icmp6 *icmp)
{
/* Build IPv6 packet */
struct mbuf *t = m_get(slirp);
struct ip6 *rip = mtod(t, struct ip6 *);
rip->ip_src = icmp->icmp6_nns.target;
if (in6_zero(&ip->ip_src)) {
rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
} else {
rip->ip_dst = ip->ip_src;
}
rip->ip_nh = IPPROTO_ICMPV6;
rip->ip_pl = htons(ICMP6_NDP_NA_MINLEN + NDPOPT_LINKLAYER_LEN);
t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
/* Build ICMPv6 packet */
t->m_data += sizeof(struct ip6);
struct icmp6 *ricmp = mtod(t, struct icmp6 *);
ricmp->icmp6_type = ICMP6_NDP_NA;
ricmp->icmp6_code = 0;
ricmp->icmp6_cksum = 0;
/* NDP */
ricmp->icmp6_nna.R = NDP_IsRouter;
ricmp->icmp6_nna.S = !IN6_IS_ADDR_MULTICAST(&rip->ip_dst);
ricmp->icmp6_nna.O = 1;
ricmp->icmp6_nna.reserved_1 = 0;
ricmp->icmp6_nna.reserved_2 = 0;
ricmp->icmp6_nna.reserved_3 = 0;
ricmp->icmp6_nna.target = icmp->icmp6_nns.target;
/* Build NDP option */
t->m_data += ICMP6_NDP_NA_MINLEN;
struct ndpopt *opt = mtod(t, struct ndpopt *);
opt->ndpopt_type = NDPOPT_LINKLAYER_TARGET;
opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
in6_compute_ethaddr(ricmp->icmp6_nna.target, opt->ndpopt_linklayer);
/* ICMPv6 Checksum */
t->m_data -= ICMP6_NDP_NA_MINLEN;
t->m_data -= sizeof(struct ip6);
ricmp->icmp6_cksum = ip6_cksum(t);
ip6_output(NULL, t, 0);
}
/*
* Process a NDP message
*/
static void ndp_input(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
struct icmp6 *icmp)
{
g_assert(M_ROOMBEFORE(m) >= ETH_HLEN);
m->m_len += ETH_HLEN;
m->m_data -= ETH_HLEN;
struct ethhdr *eth = mtod(m, struct ethhdr *);
m->m_len -= ETH_HLEN;
m->m_data += ETH_HLEN;
switch (icmp->icmp6_type) {
case ICMP6_NDP_RS:
DEBUG_CALL(" type = Router Solicitation");
if (ip->ip_hl == 255 && icmp->icmp6_code == 0 &&
ntohs(ip->ip_pl) >= ICMP6_NDP_RS_MINLEN) {
/* Gratuitous NDP */
ndp_table_add(slirp, ip->ip_src, eth->h_source);
ndp_send_ra(slirp);
}
break;
case ICMP6_NDP_RA:
DEBUG_CALL(" type = Router Advertisement");
slirp->cb->guest_error("Warning: guest sent NDP RA, but shouldn't",
slirp->opaque);
break;
case ICMP6_NDP_NS:
DEBUG_CALL(" type = Neighbor Solicitation");
if (ip->ip_hl == 255 && icmp->icmp6_code == 0 &&
!IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nns.target) &&
ntohs(ip->ip_pl) >= ICMP6_NDP_NS_MINLEN &&
(!in6_zero(&ip->ip_src) ||
in6_solicitednode_multicast(&ip->ip_dst))) {
if (in6_equal_host(&icmp->icmp6_nns.target)) {
/* Gratuitous NDP */
ndp_table_add(slirp, ip->ip_src, eth->h_source);
ndp_send_na(slirp, ip, icmp);
}
}
break;
case ICMP6_NDP_NA:
DEBUG_CALL(" type = Neighbor Advertisement");
if (ip->ip_hl == 255 && icmp->icmp6_code == 0 &&
ntohs(ip->ip_pl) >= ICMP6_NDP_NA_MINLEN &&
!IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nna.target) &&
(!IN6_IS_ADDR_MULTICAST(&ip->ip_dst) || icmp->icmp6_nna.S == 0)) {
ndp_table_add(slirp, icmp->icmp6_nna.target, eth->h_source);
}
break;
case ICMP6_NDP_REDIRECT:
DEBUG_CALL(" type = Redirect");
slirp->cb->guest_error(
"Warning: guest sent NDP REDIRECT, but shouldn't", slirp->opaque);
break;
}
}
/*
* Process a received ICMPv6 message.
*/
void icmp6_input(struct mbuf *m)
{
Slirp *slirp = m->slirp;
/* NDP reads the ethernet header for gratuitous NDP */
M_DUP_DEBUG(slirp, m, 1, ETH_HLEN);
struct icmp6 *icmp;
struct ip6 *ip = mtod(m, struct ip6 *);
int hlen = sizeof(struct ip6);
DEBUG_CALL("icmp6_input");
DEBUG_ARG("m = %p", m);
DEBUG_ARG("m_len = %d", m->m_len);
if (ntohs(ip->ip_pl) < ICMP6_MINLEN) {
freeit:
m_free(m);
goto end_error;
}
if (ip6_cksum(m)) {
goto freeit;
}
m->m_len -= hlen;
m->m_data += hlen;
icmp = mtod(m, struct icmp6 *);
m->m_len += hlen;
m->m_data -= hlen;
DEBUG_ARG("icmp6_type = %d", icmp->icmp6_type);
switch (icmp->icmp6_type) {
case ICMP6_ECHO_REQUEST:
if (in6_equal_host(&ip->ip_dst)) {
icmp6_send_echoreply(m, slirp, ip, icmp);
m_free(m);
} else if (slirp->restricted) {
goto freeit;
} else {
struct socket *so;
struct sockaddr_storage addr;
int ttl;
so = socreate(slirp, IPPROTO_ICMPV6);
if (icmp6_send(so, m, hlen) == 0) {
/* We could send this as ICMP, good! */
return;
}
/* We could not send this as ICMP, try to send it on UDP echo
* service (7), wishfully hoping that it is open there. */
if (udp_attach(so, AF_INET6) == -1) {
DEBUG_MISC("icmp6_input udp_attach errno = %d-%s", errno,
g_strerror(errno));
sofree(so);
m_free(m);
goto end_error;
}
so->so_m = m;
so->so_ffamily = AF_INET6;
so->so_faddr6 = ip->ip_dst;
so->so_fport = htons(7);
so->so_lfamily = AF_INET6;
so->so_laddr6 = ip->ip_src;
so->so_lport = htons(9);
so->so_state = SS_ISFCONNECTED;
/* Send the packet */
addr = so->fhost.ss;
if (sotranslate_out(so, &addr) < 0) {
icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
udp_detach(so);
return;
}
/*
* Check for TTL
*/
ttl = ip->ip_hl-1;
if (ttl <= 0) {
DEBUG_MISC("udp ttl exceeded");
icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);
udp_detach(so);
break;
}
setsockopt(so->s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
if (sendto(so->s, icmp6_ping_msg, strlen(icmp6_ping_msg), 0,
(struct sockaddr *)&addr, sockaddr_size(&addr)) == -1) {
DEBUG_MISC("icmp6_input udp sendto tx errno = %d-%s", errno,
g_strerror(errno));
icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
udp_detach(so);
}
} /* if (in6_equal_host(&ip->ip_dst)) */
break;
case ICMP6_NDP_RS:
case ICMP6_NDP_RA:
case ICMP6_NDP_NS:
case ICMP6_NDP_NA:
case ICMP6_NDP_REDIRECT:
ndp_input(m, slirp, ip, icmp);
m_free(m);
break;
case ICMP6_UNREACH:
case ICMP6_TOOBIG:
case ICMP6_TIMXCEED:
case ICMP6_PARAMPROB:
/* XXX? report error? close socket? */
default:
m_free(m);
break;
}
end_error:
/* m is m_free()'d xor put in a socket xor or given to ip_send */
return;
}