/* * 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 /* XXX: only DHCP is supported */ #define NB_ADDR 16 #define START_ADDR 15 #define LEASE_TIME (120) typedef struct { uint8_t allocated; uint8_t macaddr[6]; int time; } BOOTPClient; BOOTPClient bootp_clients[NB_ADDR]; static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE }; #ifdef DEBUG #define dprintf(fmt, args...) \ if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); } #else #define dprintf(fmt, args...) #endif static BOOTPClient *get_new_addr(struct in_addr *paddr) { BOOTPClient *bc; int i; int now=time(NULL); for(i = 0; i < NB_ADDR; i++) { if (!bootp_clients[i].allocated) goto found; } for(i = 0; i < NB_ADDR; i++) { if (now-bootp_clients[i].time > 3*LEASE_TIME) goto found; } return NULL; found: bc = &bootp_clients[i]; paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); return bc; } static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr) { BOOTPClient *bc; int i; for(i = 0; i < NB_ADDR; i++) { if (!memcmp(macaddr, bootp_clients[i].macaddr, 6)) goto found; } return NULL; found: bc = &bootp_clients[i]; paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); return bc; } static BOOTPClient *find_reqaddr(struct in_addr *paddr, struct in_addr *reqaddr, const uint8_t *macaddr) { BOOTPClient *bc=NULL; int i; /*check the net prefix*/ if ((ntohl(reqaddr->s_addr) & 0xffffff00) == (ntohl(special_addr.s_addr) & 0xffffff00)) { i=(ntohl(reqaddr->s_addr) & 0xff) - START_ADDR; if (i>=0 && i< NB_ADDR) { bc = &bootp_clients[i]; if (bc->allocated && (memcmp(macaddr, bootp_clients[i].macaddr, 6)==0)) { paddr->s_addr = reqaddr->s_addr; return bc; } else bc=NULL; } } return bc; } static void dhcp_decode(const uint8_t *buf, int size, int *pmsg_type, struct sockaddr_in *preqaddr) { const uint8_t *p, *p_end; int len, tag; *pmsg_type = 0; preqaddr->sin_addr.s_addr=htonl(0L); p = buf; p_end = buf + size; if (size < 5) return; 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=0x%02x 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(&(preqaddr->sin_addr),p,4); } default: break; } p += len; } } } static void bootp_reply(struct bootp_t *bp) { BOOTPClient *bc; struct mbuf *m; struct bootp_t *rbp; struct sockaddr_in saddr, daddr, reqaddr; struct in_addr dns_addr; int dhcp_msg_type, val; uint8_t *q,replytype; /* extract exact DHCP msg type */ dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type,&reqaddr); dprintf("bootp packet op=%d msgtype=%d reqaddr=%x\n", bp->bp_op, dhcp_msg_type,ntohl(reqaddr.sin_addr.s_addr)); if (dhcp_msg_type != DHCPDISCOVER && dhcp_msg_type != DHCPREQUEST) return; /* XXX: this is a hack to get the client mac address */ memcpy(client_ethaddr, bp->bp_hwaddr, 6); if ((m = m_get()) == NULL) 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)); bc=NULL; daddr.sin_addr.s_addr=htonl(0L); if (dhcp_msg_type == DHCPREQUEST) { if (reqaddr.sin_addr.s_addr != htonl(0L)) bc = find_reqaddr(&daddr.sin_addr, &reqaddr.sin_addr, bp->bp_hwaddr); else bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr); } else if (dhcp_msg_type == DHCPDISCOVER) { bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr); if (!bc) bc = get_new_addr(&daddr.sin_addr); } dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr)); saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS); 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, 6); rbp->bp_yiaddr = daddr.sin_addr; /* IP address */ q = rbp->bp_vend; memcpy(q, rfc1533_cookie, 4); q += 4; if (bc != NULL) { memcpy(bc->macaddr, client_ethaddr, 6); bc->allocated = 1; bc->time = time(NULL); replytype=(dhcp_msg_type == DHCPDISCOVER)?DHCPOFFER:DHCPACK; } else replytype=DHCPNACK; *q++ = RFC2132_MSG_TYPE; *q++ = 1; *q++ = replytype; if ((dhcp_msg_type == DHCPDISCOVER || dhcp_msg_type == DHCPREQUEST) && replytype!=DHCPNACK) { *q++ = RFC2132_SRV_ID; *q++ = 4; memcpy(q, &saddr.sin_addr, 4); q += 4; *q++ = RFC1533_NETMASK; *q++ = 4; *q++ = 0xff; *q++ = 0xff; *q++ = 0xff; *q++ = 0x00; *q++ = RFC1533_GATEWAY; *q++ = 4; memcpy(q, &saddr.sin_addr, 4); q += 4; *q++ = RFC1533_DNS; *q++ = 4; dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS); memcpy(q, &dns_addr, 4); q += 4; *q++ = RFC2132_LEASE_TIME; *q++ = 4; val = htonl(LEASE_TIME); memcpy(q, &val, 4); q += 4; } *q++ = RFC1533_END; m->m_len = sizeof(struct bootp_t); udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); } void bootp_input(struct mbuf *m) { struct bootp_t *bp = (struct bootp_t *)m->m_data; if (bp->bp_op == BOOTP_REQUEST) { bootp_reply(bp); } }