| /* | |
| * QEMU BOOTP/DHCP server | |
| * | |
| * Copyright (c) 2004 Fabrice Bellard | |
| * | |
| * Permission is hereby granted, free of charge, to any person obtaining a copy | |
| * of this software and associated documentation files (the "Software"), to deal | |
| * in the Software without restriction, including without limitation the rights | |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| * copies of the Software, and to permit persons to whom the Software is | |
| * furnished to do so, subject to the following conditions: | |
| * | |
| * The above copyright notice and this permission notice shall be included in | |
| * all copies or substantial portions of the Software. | |
| * | |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
| * THE SOFTWARE. | |
| */ | |
| #include <slirp.h> | |
| /* XXX: only DHCP is supported */ | |
| #define LEASE_TIME (24 * 3600) | |
| static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE }; | |
| #ifdef DEBUG | |
| #define DPRINTF(fmt, ...) \ | |
| do if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## __VA_ARGS__); fflush(dfd); } while (0) | |
| #else | |
| #define DPRINTF(fmt, ...) do{}while(0) | |
| #endif | |
| static BOOTPClient *get_new_addr(Slirp *slirp, struct in_addr *paddr, | |
| const uint8_t *macaddr) | |
| { | |
| BOOTPClient *bc; | |
| int i; | |
| for(i = 0; i < NB_BOOTP_CLIENTS; i++) { | |
| bc = &slirp->bootp_clients[i]; | |
| if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) | |
| goto found; | |
| } | |
| return NULL; | |
| found: | |
| bc = &slirp->bootp_clients[i]; | |
| bc->allocated = 1; | |
| paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i); | |
| return bc; | |
| } | |
| static BOOTPClient *request_addr(Slirp *slirp, const struct in_addr *paddr, | |
| const uint8_t *macaddr) | |
| { | |
| uint32_t req_addr = ntohl(paddr->s_addr); | |
| uint32_t dhcp_addr = ntohl(slirp->vdhcp_startaddr.s_addr); | |
| BOOTPClient *bc; | |
| if (req_addr >= dhcp_addr && | |
| req_addr < (dhcp_addr + NB_BOOTP_CLIENTS)) { | |
| bc = &slirp->bootp_clients[req_addr - dhcp_addr]; | |
| if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) { | |
| bc->allocated = 1; | |
| return bc; | |
| } | |
| } | |
| return NULL; | |
| } | |
| static BOOTPClient *find_addr(Slirp *slirp, struct in_addr *paddr, | |
| const uint8_t *macaddr) | |
| { | |
| BOOTPClient *bc; | |
| int i; | |
| for(i = 0; i < NB_BOOTP_CLIENTS; i++) { | |
| if (!memcmp(macaddr, slirp->bootp_clients[i].macaddr, 6)) | |
| goto found; | |
| } | |
| return NULL; | |
| found: | |
| bc = &slirp->bootp_clients[i]; | |
| bc->allocated = 1; | |
| paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i); | |
| return bc; | |
| } | |
| static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type, | |
| struct in_addr *preq_addr) | |
| { | |
| const uint8_t *p, *p_end; | |
| int len, tag; | |
| *pmsg_type = 0; | |
| preq_addr->s_addr = htonl(0L); | |
| p = bp->bp_vend; | |
| p_end = p + DHCP_OPT_LEN; | |
| if (memcmp(p, rfc1533_cookie, 4) != 0) | |
| return; | |
| p += 4; | |
| while (p < p_end) { | |
| tag = p[0]; | |
| if (tag == RFC1533_PAD) { | |
| p++; | |
| } else if (tag == RFC1533_END) { | |
| break; | |
| } else { | |
| p++; | |
| if (p >= p_end) | |
| break; | |
| len = *p++; | |
| DPRINTF("dhcp: tag=%d len=%d\n", tag, len); | |
| switch(tag) { | |
| case RFC2132_MSG_TYPE: | |
| if (len >= 1) | |
| *pmsg_type = p[0]; | |
| break; | |
| case RFC2132_REQ_ADDR: | |
| if (len >= 4) { | |
| memcpy(&(preq_addr->s_addr), p, 4); | |
| } | |
| break; | |
| default: | |
| break; | |
| } | |
| p += len; | |
| } | |
| } | |
| if (*pmsg_type == DHCPREQUEST && preq_addr->s_addr == htonl(0L) && | |
| bp->bp_ciaddr.s_addr) { | |
| memcpy(&(preq_addr->s_addr), &bp->bp_ciaddr, 4); | |
| } | |
| } | |
| 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=%08x\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=%08x\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=%08x\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); | |
| } | |
| void bootp_input(struct mbuf *m) | |
| { | |
| struct bootp_t *bp = mtod(m, struct bootp_t *); | |
| if (bp->bp_op == BOOTP_REQUEST) { | |
| bootp_reply(m->slirp, bp); | |
| } | |
| } |