diff options
Diffstat (limited to 'slirp/bootp.c')
| -rw-r--r-- | slirp/bootp.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/slirp/bootp.c b/slirp/bootp.c new file mode 100644 index 00000000..b7db9fa3 --- /dev/null +++ b/slirp/bootp.c @@ -0,0 +1,332 @@ +/* + * 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); + } +} |