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/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (c) 2013
* Guillaume Subiron
*/
#include "slirp.h"
#include "udp.h"
#include "dhcpv6.h"
void udp6_input(struct mbuf *m)
{
Slirp *slirp = m->slirp;
struct ip6 *ip, save_ip;
struct udphdr *uh;
int iphlen = sizeof(struct ip6);
int len;
struct socket *so;
struct sockaddr_in6 lhost;
int hop_limit;
DEBUG_CALL("udp6_input");
DEBUG_ARG("m = %p", m);
if (slirp->restricted) {
goto bad;
}
ip = mtod(m, struct ip6 *);
m->m_len -= iphlen;
m->m_data += iphlen;
uh = mtod(m, struct udphdr *);
m->m_len += iphlen;
m->m_data -= iphlen;
if (ip6_cksum(m)) {
goto bad;
}
len = ntohs((uint16_t)uh->uh_ulen);
/*
* Make mbuf data length reflect UDP length.
* If not enough data to reflect UDP length, drop.
*/
if (ntohs(ip->ip_pl) != len) {
if (len > ntohs(ip->ip_pl)) {
goto bad;
}
m_adj(m, len - ntohs(ip->ip_pl));
ip->ip_pl = htons(len);
}
/*
* Save a copy of the IP header in case we want restore it
* for sending an ICMP error message in response.
*/
save_ip = *ip;
/* Locate pcb for datagram. */
lhost.sin6_family = AF_INET6;
lhost.sin6_addr = ip->ip_src;
lhost.sin6_port = uh->uh_sport;
/* handle DHCPv6 */
if (ntohs(uh->uh_dport) == DHCPV6_SERVER_PORT &&
(in6_equal(&ip->ip_dst, &slirp->vhost_addr6) ||
in6_dhcp_multicast(&ip->ip_dst))) {
m->m_data += iphlen;
m->m_len -= iphlen;
dhcpv6_input(&lhost, m);
m->m_data -= iphlen;
m->m_len += iphlen;
goto bad;
}
/* handle TFTP */
if (ntohs(uh->uh_dport) == TFTP_SERVER &&
!memcmp(ip->ip_dst.s6_addr, slirp->vhost_addr6.s6_addr, 16)) {
m->m_data += iphlen;
m->m_len -= iphlen;
tftp_input((struct sockaddr_storage *)&lhost, m);
m->m_data -= iphlen;
m->m_len += iphlen;
goto bad;
}
so = solookup(&slirp->udp_last_so, &slirp->udb,
(struct sockaddr_storage *)&lhost, NULL);
if (so == NULL) {
/* If there's no socket for this packet, create one. */
so = socreate(slirp);
if (udp_attach(so, AF_INET6) == -1) {
DEBUG_MISC(" udp6_attach errno = %d-%s", errno, strerror(errno));
sofree(so);
goto bad;
}
/* Setup fields */
so->so_lfamily = AF_INET6;
so->so_laddr6 = ip->ip_src;
so->so_lport6 = uh->uh_sport;
}
so->so_ffamily = AF_INET6;
so->so_faddr6 = ip->ip_dst; /* XXX */
so->so_fport6 = uh->uh_dport; /* XXX */
iphlen += sizeof(struct udphdr);
m->m_len -= iphlen;
m->m_data += iphlen;
/*
* Check for TTL
*/
hop_limit = save_ip.ip_hl-1;
if (hop_limit <= 0) {
m->m_len += iphlen;
m->m_data -= iphlen;
*ip = save_ip;
DEBUG_MISC("udp ttl exceeded");
icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);
goto bad;
}
setsockopt(so->s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hop_limit, sizeof(hop_limit));
/*
* Now we sendto() the packet.
*/
if (sosendto(so, m) == -1) {
m->m_len += iphlen;
m->m_data -= iphlen;
*ip = save_ip;
DEBUG_MISC("udp tx errno = %d-%s", errno, strerror(errno));
icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
goto bad;
}
m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
/* restore the orig mbuf packet */
m->m_len += iphlen;
m->m_data -= iphlen;
*ip = save_ip;
so->so_m = m;
return;
bad:
m_free(m);
}
int udp6_output(struct socket *so, struct mbuf *m, struct sockaddr_in6 *saddr,
struct sockaddr_in6 *daddr)
{
g_assert(M_ROOMBEFORE(m) >= sizeof(struct ip6) + sizeof(struct udphdr));
struct ip6 *ip;
struct udphdr *uh;
DEBUG_CALL("udp6_output");
DEBUG_ARG("so = %p", so);
DEBUG_ARG("m = %p", m);
/* adjust for header */
m->m_data -= sizeof(struct udphdr);
m->m_len += sizeof(struct udphdr);
uh = mtod(m, struct udphdr *);
m->m_data -= sizeof(struct ip6);
m->m_len += sizeof(struct ip6);
ip = mtod(m, struct ip6 *);
/* Build IP header */
ip->ip_pl = htons(m->m_len - sizeof(struct ip6));
ip->ip_nh = IPPROTO_UDP;
ip->ip_src = saddr->sin6_addr;
ip->ip_dst = daddr->sin6_addr;
/* Build UDP header */
uh->uh_sport = saddr->sin6_port;
uh->uh_dport = daddr->sin6_port;
uh->uh_ulen = ip->ip_pl;
uh->uh_sum = 0;
uh->uh_sum = ip6_cksum(m);
if (uh->uh_sum == 0) {
uh->uh_sum = 0xffff;
}
return ip6_output(so, m, 0);
}
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