slirp/udp6.c

   1 /*
   2  * Copyright (c) 2013
   3  * Guillaume Subiron
   4  */
   5
   6 #include "qemu/osdep.h"
   7 #include "qemu-common.h"
   8 #include "slirp.h"
   9 #include "udp.h"
  10 #include "dhcpv6.h"
  11
  12 void udp6_input(struct mbuf *m)
  13 {
  14     Slirp *slirp = m->slirp;
  15     struct ip6 *ip, save_ip;
  16     struct udphdr *uh;
  17     int iphlen = sizeof(struct ip6);
  18     int len;
  19     struct socket *so;
  20     struct sockaddr_in6 lhost;
  21
  22     DEBUG_CALL("udp6_input");
  23     DEBUG_ARG("m = %lx", (long)m);
  24
  25     if (slirp->restricted) {
  26         goto bad;
  27     }
  28
  29     ip = mtod(m, struct ip6 *);
  30     m->m_len -= iphlen;
  31     m->m_data += iphlen;
  32     uh = mtod(m, struct udphdr *);
  33     m->m_len += iphlen;
  34     m->m_data -= iphlen;
  35
  36     if (ip6_cksum(m)) {
  37         goto bad;
  38     }
  39
  40     len = ntohs((uint16_t)uh->uh_ulen);
  41
  42     /*
  43      * Make mbuf data length reflect UDP length.
  44      * If not enough data to reflect UDP length, drop.
  45      */
  46     if (ntohs(ip->ip_pl) != len) {
  47         if (len > ntohs(ip->ip_pl)) {
  48             goto bad;
  49         }
  50         m_adj(m, len - ntohs(ip->ip_pl));
  51         ip->ip_pl = htons(len);
  52     }
  53
  54     /*
  55      * Save a copy of the IP header in case we want restore it
  56      * for sending an ICMP error message in response.
  57      */
  58     save_ip = *ip;
  59
  60     /* Locate pcb for datagram. */
  61     lhost.sin6_family = AF_INET6;
  62     lhost.sin6_addr = ip->ip_src;
  63     lhost.sin6_port = uh->uh_sport;
  64
  65     /* handle DHCPv6 */
  66     if (ntohs(uh->uh_dport) == DHCPV6_SERVER_PORT &&
  67         (in6_equal(&ip->ip_dst, &slirp->vhost_addr6) ||
  68          in6_dhcp_multicast(&ip->ip_dst))) {
  69         m->m_data += iphlen;
  70         m->m_len -= iphlen;
  71         dhcpv6_input(&lhost, m);
  72         m->m_data -= iphlen;
  73         m->m_len += iphlen;
  74         goto bad;
  75     }
  76
  77     /* handle TFTP */
  78     if (ntohs(uh->uh_dport) == TFTP_SERVER &&
  79         !memcmp(ip->ip_dst.s6_addr, slirp->vhost_addr6.s6_addr, 16)) {
  80         m->m_data += iphlen;
  81         m->m_len -= iphlen;
  82         tftp_input((struct sockaddr_storage *)&lhost, m);
  83         m->m_data -= iphlen;
  84         m->m_len += iphlen;
  85         goto bad;
  86     }
  87
  88     so = solookup(&slirp->udp_last_so, &slirp->udb,
  89                   (struct sockaddr_storage *) &lhost, NULL);
  90
  91     if (so == NULL) {
  92         /* If there's no socket for this packet, create one. */
  93         so = socreate(slirp);
  94         if (udp_attach(so, AF_INET6) == -1) {
  95             DEBUG_MISC((dfd, " udp6_attach errno = %d-%s\n",
  96                         errno, strerror(errno)));
  97             sofree(so);
  98             goto bad;
  99         }
 100
 101         /* Setup fields */
 102         so->so_lfamily = AF_INET6;
 103         so->so_laddr6 = ip->ip_src;
 104         so->so_lport6 = uh->uh_sport;
 105     }
 106
 107     so->so_ffamily = AF_INET6;
 108     so->so_faddr6 = ip->ip_dst; /* XXX */
 109     so->so_fport6 = uh->uh_dport; /* XXX */
 110
 111     iphlen += sizeof(struct udphdr);
 112     m->m_len -= iphlen;
 113     m->m_data += iphlen;
 114
 115     /*
 116      * Now we sendto() the packet.
 117      */
 118     if (sosendto(so, m) == -1) {
 119         m->m_len += iphlen;
 120         m->m_data -= iphlen;
 121         *ip = save_ip;
 122         DEBUG_MISC((dfd, "udp tx errno = %d-%s\n", errno, strerror(errno)));
 123         icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
 124         goto bad;
 125     }
 126
 127     m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 128
 129     /* restore the orig mbuf packet */
 130     m->m_len += iphlen;
 131     m->m_data -= iphlen;
 132     *ip = save_ip;
 133     so->so_m = m;
 134
 135     return;
 136 bad:
 137     m_free(m);
 138 }
 139
 140 int udp6_output(struct socket *so, struct mbuf *m,
 141         struct sockaddr_in6 *saddr, struct sockaddr_in6 *daddr)
 142 {
 143     struct ip6 *ip;
 144     struct udphdr *uh;
 145
 146     DEBUG_CALL("udp6_output");
 147     DEBUG_ARG("so = %lx", (long)so);
 148     DEBUG_ARG("m = %lx", (long)m);
 149
 150     /* adjust for header */
 151     m->m_data -= sizeof(struct udphdr);
 152     m->m_len += sizeof(struct udphdr);
 153     uh = mtod(m, struct udphdr *);
 154     m->m_data -= sizeof(struct ip6);
 155     m->m_len += sizeof(struct ip6);
 156     ip = mtod(m, struct ip6 *);
 157
 158     /* Build IP header */
 159     ip->ip_pl = htons(m->m_len - sizeof(struct ip6));
 160     ip->ip_nh = IPPROTO_UDP;
 161     ip->ip_src = saddr->sin6_addr;
 162     ip->ip_dst = daddr->sin6_addr;
 163
 164     /* Build UDP header */
 165     uh->uh_sport = saddr->sin6_port;
 166     uh->uh_dport = daddr->sin6_port;
 167     uh->uh_ulen = ip->ip_pl;
 168     uh->uh_sum = 0;
 169     uh->uh_sum = ip6_cksum(m);
 170     if (uh->uh_sum == 0) {
 171         uh->uh_sum = 0xffff;
 172     }
 173
 174     return ip6_output(so, m, 0);
 175 }