| /* |
| * 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 NB_ADDR 16 |
| |
| #define START_ADDR 15 |
| |
| #define LEASE_TIME (24 * 3600) |
| |
| typedef struct { |
| uint8_t allocated; |
| uint8_t macaddr[6]; |
| } BOOTPClient; |
| |
| static BOOTPClient bootp_clients[NB_ADDR]; |
| |
| const char *bootp_filename; |
| |
| 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; |
| |
| for(i = 0; i < NB_ADDR; i++) { |
| if (!bootp_clients[i].allocated) |
| goto found; |
| } |
| return NULL; |
| found: |
| bc = &bootp_clients[i]; |
| bc->allocated = 1; |
| paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
| return bc; |
| } |
| |
| static BOOTPClient *request_addr(const struct in_addr *paddr, |
| const uint8_t *macaddr) |
| { |
| uint32_t req_addr = ntohl(paddr->s_addr); |
| uint32_t spec_addr = ntohl(special_addr.s_addr); |
| BOOTPClient *bc; |
| |
| if (req_addr >= (spec_addr | START_ADDR) && |
| req_addr < (spec_addr | (NB_ADDR + START_ADDR))) { |
| bc = &bootp_clients[(req_addr & 0xff) - START_ADDR]; |
| if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) { |
| bc->allocated = 1; |
| return bc; |
| } |
| } |
| return NULL; |
| } |
| |
| 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]; |
| bc->allocated = 1; |
| paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
| return bc; |
| } |
| |
| static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type, |
| const struct in_addr **preq_addr) |
| { |
| const uint8_t *p, *p_end; |
| int len, tag; |
| |
| *pmsg_type = 0; |
| *preq_addr = NULL; |
| |
| 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) |
| *preq_addr = (struct in_addr *)p; |
| break; |
| default: |
| break; |
| } |
| p += len; |
| } |
| } |
| if (*pmsg_type == DHCPREQUEST && !*preq_addr && bp->bp_ciaddr.s_addr) { |
| *preq_addr = &bp->bp_ciaddr; |
| } |
| } |
| |
| static void bootp_reply(const struct bootp_t *bp) |
| { |
| BOOTPClient *bc = NULL; |
| struct mbuf *m; |
| struct bootp_t *rbp; |
| struct sockaddr_in saddr, daddr; |
| struct in_addr dns_addr; |
| const struct in_addr *preq_addr; |
| int dhcp_msg_type, val; |
| uint8_t *q; |
| |
| /* 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) |
| 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; |
| /* 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)); |
| |
| if (dhcp_msg_type == DHCPDISCOVER) { |
| if (preq_addr) { |
| bc = request_addr(preq_addr, client_ethaddr); |
| if (bc) { |
| daddr.sin_addr = *preq_addr; |
| } |
| } |
| if (!bc) { |
| new_addr: |
| bc = get_new_addr(&daddr.sin_addr); |
| if (!bc) { |
| dprintf("no address left\n"); |
| return; |
| } |
| } |
| memcpy(bc->macaddr, client_ethaddr, 6); |
| } else if (preq_addr) { |
| bc = request_addr(preq_addr, client_ethaddr); |
| if (bc) { |
| daddr.sin_addr = *preq_addr; |
| memcpy(bc->macaddr, client_ethaddr, 6); |
| } else { |
| daddr.sin_addr.s_addr = 0; |
| } |
| } else { |
| bc = find_addr(&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; |
| } |
| } |
| |
| 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; /* 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 (bootp_filename) |
| snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s", |
| bootp_filename); |
| |
| *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; |
| |
| if (!slirp_restrict) { |
| *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; |
| |
| if (*slirp_hostname) { |
| val = strlen(slirp_hostname); |
| *q++ = RFC1533_HOSTNAME; |
| *q++ = val; |
| memcpy(q, slirp_hostname, 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(bp); |
| } |
| } |
