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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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|
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/* XXX: only DHCP is supported */ |
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|
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#define NB_ADDR 16 |
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|
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#define START_ADDR 15 |
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|
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#define LEASE_TIME (24 * 3600) |
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|
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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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|
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BOOTPClient bootp_clients[NB_ADDR]; |
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|
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static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE }; |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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static void dhcp_decode(const uint8_t *buf, int size, |
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int *pmsg_type) |
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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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|
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*pmsg_type = 0; |
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|
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p = buf; |
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p_end = buf + size; |
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if (size < 5) |
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return; |
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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=0x%02x len=%d\n", tag, len); |
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|
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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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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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} |
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|
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static void bootp_reply(struct bootp_t *bp) |
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{ |
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BOOTPClient *bc; |
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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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int dhcp_msg_type, val; |
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uint8_t *q; |
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|
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/* extract exact DHCP msg type */ |
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dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type); |
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dprintf("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type); |
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|
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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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|
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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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|
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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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|
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if (dhcp_msg_type == DHCPDISCOVER) { |
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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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memcpy(bc->macaddr, client_ethaddr, 6); |
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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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dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr)); |
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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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|
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daddr.sin_port = htons(BOOTP_CLIENT); |
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|
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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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|
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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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|
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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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|
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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 if (dhcp_msg_type == 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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|
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if (dhcp_msg_type == DHCPDISCOVER || |
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dhcp_msg_type == DHCPREQUEST) { |
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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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|
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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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|
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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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|
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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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} |
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*q++ = RFC1533_END; |
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|
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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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|
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void bootp_input(struct mbuf *m) |
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{ |
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struct bootp_t *bp = (struct bootp_t *)m->m_data; |
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|
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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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} |
