static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) { BOOTPClient *bc = NULL; struct mbuf *m; struct bootp_t *rbp; struct sockaddr_in saddr, daddr; struct in_addr preq_addr; int dhcp_msg_type, val; uint8_t *q; uint8_t client_ethaddr[ETH_ALEN]; /* extract exact DHCP msg type */ dhcp_decode(bp, &dhcp_msg_type, &preq_addr); DPRINTF("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type); if (preq_addr.s_addr != htonl(0L)) DPRINTF(" req_addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr)); else DPRINTF("\n"); if (dhcp_msg_type == 0) dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */ if (dhcp_msg_type != DHCPDISCOVER && dhcp_msg_type != DHCPREQUEST) return; /* Get client's hardware address from bootp request */ memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN); m = m_get(slirp); if (!m) { return; } m->m_data += IF_MAXLINKHDR; rbp = (struct bootp_t *)m->m_data; m->m_data += sizeof(struct udpiphdr); memset(rbp, 0, sizeof(struct bootp_t)); if (dhcp_msg_type == DHCPDISCOVER) { if (preq_addr.s_addr != htonl(0L)) { bc = request_addr(slirp, &preq_addr, client_ethaddr); if (bc) { daddr.sin_addr = preq_addr; } } if (!bc) { new_addr: bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr); if (!bc) { DPRINTF("no address left\n"); return; } } memcpy(bc->macaddr, client_ethaddr, ETH_ALEN); } else if (preq_addr.s_addr != htonl(0L)) { bc = request_addr(slirp, &preq_addr, client_ethaddr); if (bc) { daddr.sin_addr = preq_addr; memcpy(bc->macaddr, client_ethaddr, ETH_ALEN); } else { /* DHCPNAKs should be sent to broadcast */ daddr.sin_addr.s_addr = 0xffffffff; } } else { bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr); if (!bc) { /* if never assigned, behaves as if it was already assigned (windows fix because it remembers its address) */ goto new_addr; } } /* Update ARP table for this IP address */ arp_table_add(slirp, daddr.sin_addr.s_addr, client_ethaddr); saddr.sin_addr = slirp->vhost_addr; saddr.sin_port = htons(BOOTP_SERVER); daddr.sin_port = htons(BOOTP_CLIENT); rbp->bp_op = BOOTP_REPLY; rbp->bp_xid = bp->bp_xid; rbp->bp_htype = 1; rbp->bp_hlen = 6; memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN); rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */ rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */ q = rbp->bp_vend; memcpy(q, rfc1533_cookie, 4); q += 4; if (bc) { DPRINTF("%s addr=%08" PRIx32 "\n", (dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed", ntohl(daddr.sin_addr.s_addr)); if (dhcp_msg_type == DHCPDISCOVER) { *q++ = RFC2132_MSG_TYPE; *q++ = 1; *q++ = DHCPOFFER; } else /* DHCPREQUEST */ { *q++ = RFC2132_MSG_TYPE; *q++ = 1; *q++ = DHCPACK; } if (slirp->bootp_filename) snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s", slirp->bootp_filename); *q++ = RFC2132_SRV_ID; *q++ = 4; memcpy(q, &saddr.sin_addr, 4); q += 4; *q++ = RFC1533_NETMASK; *q++ = 4; memcpy(q, &slirp->vnetwork_mask, 4); q += 4; if (!slirp->restricted) { *q++ = RFC1533_GATEWAY; *q++ = 4; memcpy(q, &saddr.sin_addr, 4); q += 4; *q++ = RFC1533_DNS; *q++ = 4; memcpy(q, &slirp->vnameserver_addr, 4); q += 4; } *q++ = RFC2132_LEASE_TIME; *q++ = 4; val = htonl(LEASE_TIME); memcpy(q, &val, 4); q += 4; if (*slirp->client_hostname) { val = strlen(slirp->client_hostname); *q++ = RFC1533_HOSTNAME; *q++ = val; memcpy(q, slirp->client_hostname, val); q += val; } if (slirp->vdnssearch) { size_t spaceleft = sizeof(rbp->bp_vend) - (q - rbp->bp_vend); val = slirp->vdnssearch_len; if (val + 1 > spaceleft) { g_warning("DHCP packet size exceeded, " "omitting domain-search option."); } else { memcpy(q, slirp->vdnssearch, val); q += val; } } } else { static const char nak_msg[] = "requested address not available"; DPRINTF("nak'ed addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr)); *q++ = RFC2132_MSG_TYPE; *q++ = 1; *q++ = DHCPNAK; *q++ = RFC2132_MESSAGE; *q++ = sizeof(nak_msg) - 1; memcpy(q, nak_msg, sizeof(nak_msg) - 1); q += sizeof(nak_msg) - 1; } *q = RFC1533_END; daddr.sin_addr.s_addr = 0xffffffffu; m->m_len = sizeof(struct bootp_t) - sizeof(struct ip) - sizeof(struct udphdr); udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); }