root / slirp / bootp.c @ d084469c
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/*
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* QEMU BOOTP/DHCP server
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*
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* Copyright (c) 2004 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <slirp.h> |
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/* XXX: only DHCP is supported */
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#define NB_ADDR 16 |
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#define START_ADDR 15 |
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#define LEASE_TIME (24 * 3600) |
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typedef struct { |
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uint8_t allocated; |
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uint8_t macaddr[6];
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} BOOTPClient; |
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static BOOTPClient bootp_clients[NB_ADDR];
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const char *bootp_filename; |
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static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE }; |
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#ifdef DEBUG
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#define dprintf(fmt, args...) \
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if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); } |
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#else
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#define dprintf(fmt, args...)
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#endif
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static BOOTPClient *get_new_addr(struct in_addr *paddr) |
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{ |
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BOOTPClient *bc; |
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int i;
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for(i = 0; i < NB_ADDR; i++) { |
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if (!bootp_clients[i].allocated)
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goto found;
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} |
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return NULL; |
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found:
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bc = &bootp_clients[i]; |
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bc->allocated = 1;
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paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
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return bc;
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} |
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static BOOTPClient *request_addr(const struct in_addr *paddr, |
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const uint8_t *macaddr)
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{ |
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uint32_t req_addr = ntohl(paddr->s_addr); |
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uint32_t spec_addr = ntohl(special_addr.s_addr); |
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BOOTPClient *bc; |
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if (req_addr >= (spec_addr | START_ADDR) &&
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req_addr < (spec_addr | (NB_ADDR + START_ADDR))) { |
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bc = &bootp_clients[(req_addr & 0xff) - START_ADDR];
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if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) { |
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bc->allocated = 1;
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return bc;
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} |
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} |
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return NULL; |
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} |
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static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr) |
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{ |
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BOOTPClient *bc; |
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int i;
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for(i = 0; i < NB_ADDR; i++) { |
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if (!memcmp(macaddr, bootp_clients[i].macaddr, 6)) |
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goto found;
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} |
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return NULL; |
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found:
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bc = &bootp_clients[i]; |
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bc->allocated = 1;
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paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
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return bc;
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} |
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static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type, |
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const struct in_addr **preq_addr) |
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{ |
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const uint8_t *p, *p_end;
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int len, tag;
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*pmsg_type = 0;
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*preq_addr = NULL;
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p = bp->bp_vend; |
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p_end = p + DHCP_OPT_LEN; |
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if (memcmp(p, rfc1533_cookie, 4) != 0) |
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return;
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p += 4;
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while (p < p_end) {
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tag = p[0];
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if (tag == RFC1533_PAD) {
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p++; |
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} else if (tag == RFC1533_END) { |
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break;
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} else {
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p++; |
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if (p >= p_end)
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break;
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len = *p++; |
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dprintf("dhcp: tag=%d len=%d\n", tag, len);
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switch(tag) {
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case RFC2132_MSG_TYPE:
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if (len >= 1) |
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*pmsg_type = p[0];
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break;
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case RFC2132_REQ_ADDR:
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if (len >= 4) |
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*preq_addr = (struct in_addr *)p;
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break;
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default:
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break;
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} |
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p += len; |
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} |
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} |
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if (*pmsg_type == DHCPREQUEST && !*preq_addr && bp->bp_ciaddr.s_addr) {
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*preq_addr = &bp->bp_ciaddr; |
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} |
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} |
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static void bootp_reply(const struct bootp_t *bp) |
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{ |
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BOOTPClient *bc = NULL;
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struct mbuf *m;
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struct bootp_t *rbp;
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struct sockaddr_in saddr, daddr;
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struct in_addr dns_addr;
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const struct in_addr *preq_addr; |
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int dhcp_msg_type, val;
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uint8_t *q; |
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/* extract exact DHCP msg type */
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dhcp_decode(bp, &dhcp_msg_type, &preq_addr); |
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dprintf("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
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if (preq_addr)
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dprintf(" req_addr=%08x\n", ntohl(preq_addr->s_addr));
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else
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dprintf("\n");
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if (dhcp_msg_type == 0) |
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dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
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if (dhcp_msg_type != DHCPDISCOVER &&
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dhcp_msg_type != DHCPREQUEST) |
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return;
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/* XXX: this is a hack to get the client mac address */
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memcpy(client_ethaddr, bp->bp_hwaddr, 6);
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if ((m = m_get()) == NULL) |
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return;
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m->m_data += IF_MAXLINKHDR; |
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rbp = (struct bootp_t *)m->m_data;
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m->m_data += sizeof(struct udpiphdr); |
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memset(rbp, 0, sizeof(struct bootp_t)); |
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if (dhcp_msg_type == DHCPDISCOVER) {
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if (preq_addr) {
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bc = request_addr(preq_addr, client_ethaddr); |
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if (bc) {
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daddr.sin_addr = *preq_addr; |
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} |
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} |
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if (!bc) {
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new_addr:
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bc = get_new_addr(&daddr.sin_addr); |
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if (!bc) {
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dprintf("no address left\n");
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return;
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} |
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} |
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memcpy(bc->macaddr, client_ethaddr, 6);
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} else if (preq_addr) { |
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bc = request_addr(preq_addr, client_ethaddr); |
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if (bc) {
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daddr.sin_addr = *preq_addr; |
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memcpy(bc->macaddr, client_ethaddr, 6);
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} else {
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daddr.sin_addr.s_addr = 0;
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} |
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} else {
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bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr); |
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if (!bc) {
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/* if never assigned, behaves as if it was already
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assigned (windows fix because it remembers its address) */
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goto new_addr;
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} |
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} |
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saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS); |
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saddr.sin_port = htons(BOOTP_SERVER); |
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daddr.sin_port = htons(BOOTP_CLIENT); |
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rbp->bp_op = BOOTP_REPLY; |
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rbp->bp_xid = bp->bp_xid; |
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rbp->bp_htype = 1;
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rbp->bp_hlen = 6;
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memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
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rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
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rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
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q = rbp->bp_vend; |
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memcpy(q, rfc1533_cookie, 4);
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q += 4;
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if (bc) {
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dprintf("%s addr=%08x\n",
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(dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed", |
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ntohl(daddr.sin_addr.s_addr)); |
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if (dhcp_msg_type == DHCPDISCOVER) {
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*q++ = RFC2132_MSG_TYPE; |
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*q++ = 1;
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*q++ = DHCPOFFER; |
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} else /* DHCPREQUEST */ { |
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*q++ = RFC2132_MSG_TYPE; |
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*q++ = 1;
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*q++ = DHCPACK; |
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} |
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if (bootp_filename)
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snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s", |
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bootp_filename); |
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*q++ = RFC2132_SRV_ID; |
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*q++ = 4;
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memcpy(q, &saddr.sin_addr, 4);
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q += 4;
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*q++ = RFC1533_NETMASK; |
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*q++ = 4;
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*q++ = 0xff;
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*q++ = 0xff;
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*q++ = 0xff;
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*q++ = 0x00;
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if (!slirp_restrict) {
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*q++ = RFC1533_GATEWAY; |
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*q++ = 4;
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memcpy(q, &saddr.sin_addr, 4);
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q += 4;
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*q++ = RFC1533_DNS; |
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*q++ = 4;
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dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS); |
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memcpy(q, &dns_addr, 4);
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q += 4;
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} |
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*q++ = RFC2132_LEASE_TIME; |
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*q++ = 4;
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val = htonl(LEASE_TIME); |
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memcpy(q, &val, 4);
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q += 4;
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if (*slirp_hostname) {
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val = strlen(slirp_hostname); |
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*q++ = RFC1533_HOSTNAME; |
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*q++ = val; |
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memcpy(q, slirp_hostname, val); |
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q += val; |
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} |
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} else {
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static const char nak_msg[] = "requested address not available"; |
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dprintf("nak'ed addr=%08x\n", ntohl(preq_addr->s_addr));
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*q++ = RFC2132_MSG_TYPE; |
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*q++ = 1;
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*q++ = DHCPNAK; |
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*q++ = RFC2132_MESSAGE; |
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*q++ = sizeof(nak_msg) - 1; |
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memcpy(q, nak_msg, sizeof(nak_msg) - 1); |
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q += sizeof(nak_msg) - 1; |
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} |
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*q++ = RFC1533_END; |
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daddr.sin_addr.s_addr = 0xffffffffu;
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m->m_len = sizeof(struct bootp_t) - |
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sizeof(struct ip) - sizeof(struct udphdr); |
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udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
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} |
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void bootp_input(struct mbuf *m) |
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{ |
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struct bootp_t *bp = mtod(m, struct bootp_t *); |
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if (bp->bp_op == BOOTP_REQUEST) {
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bootp_reply(bp); |
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} |
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} |