diff options
| -rw-r--r-- | slirp/slirp.c | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/slirp/slirp.c b/slirp/slirp.c index a975b3e359..a66ba674d2 100644 --- a/slirp/slirp.c +++ b/slirp/slirp.c @@ -16,7 +16,11 @@ static const uint8_t special_ethaddr[6] = { 0x52, 0x54, 0x00, 0x12, 0x35, 0x00 }; +/* ARP cache for the guest IP addresses (XXX: allow many entries) */ uint8_t client_ethaddr[6]; +static struct in_addr client_ipaddr; + +static const uint8_t zero_ethaddr[6] = { 0, 0, 0, 0, 0, 0 }; int do_slowtimo; int link_up; @@ -597,6 +601,13 @@ static void arp_input(const uint8_t *pkt, int pkt_len) slirp_output(arp_reply, sizeof(arp_reply)); } break; + case ARPOP_REPLY: + /* reply to request of client mac address ? */ + if (!memcmp(client_ethaddr, zero_ethaddr, ETH_ALEN) && + !memcmp(ah->ar_sip, &client_ipaddr.s_addr, 4)) { + memcpy(client_ethaddr, ah->ar_sha, ETH_ALEN); + } + break; default: break; } @@ -641,14 +652,47 @@ void if_encap(const uint8_t *ip_data, int ip_data_len) if (ip_data_len + ETH_HLEN > sizeof(buf)) return; - - memcpy(eh->h_dest, client_ethaddr, ETH_ALEN); - memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1); - /* XXX: not correct */ - eh->h_source[5] = CTL_ALIAS; - eh->h_proto = htons(ETH_P_IP); - memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len); - slirp_output(buf, ip_data_len + ETH_HLEN); + + if (!memcmp(client_ethaddr, zero_ethaddr, ETH_ALEN)) { + uint8_t arp_req[ETH_HLEN + sizeof(struct arphdr)]; + struct ethhdr *reh = (struct ethhdr *)arp_req; + struct arphdr *rah = (struct arphdr *)(arp_req + ETH_HLEN); + const struct ip *iph = (const struct ip *)ip_data; + + /* If the client addr is not known, there is no point in + sending the packet to it. Normally the sender should have + done an ARP request to get its MAC address. Here we do it + in place of sending the packet and we hope that the sender + will retry sending its packet. */ + memset(reh->h_dest, 0xff, ETH_ALEN); + memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1); + reh->h_source[5] = CTL_ALIAS; + reh->h_proto = htons(ETH_P_ARP); + rah->ar_hrd = htons(1); + rah->ar_pro = htons(ETH_P_IP); + rah->ar_hln = ETH_ALEN; + rah->ar_pln = 4; + rah->ar_op = htons(ARPOP_REQUEST); + /* source hw addr */ + memcpy(rah->ar_sha, special_ethaddr, ETH_ALEN - 1); + rah->ar_sha[5] = CTL_ALIAS; + /* source IP */ + memcpy(rah->ar_sip, &alias_addr, 4); + /* target hw addr (none) */ + memset(rah->ar_tha, 0, ETH_ALEN); + /* target IP */ + memcpy(rah->ar_tip, &iph->ip_dst, 4); + client_ipaddr = iph->ip_dst; + slirp_output(arp_req, sizeof(arp_req)); + } else { + memcpy(eh->h_dest, client_ethaddr, ETH_ALEN); + memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1); + /* XXX: not correct */ + eh->h_source[5] = CTL_ALIAS; + eh->h_proto = htons(ETH_P_IP); + memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len); + slirp_output(buf, ip_data_len + ETH_HLEN); + } } int slirp_redir(int is_udp, int host_port, |