root / slirp / bootp.c @ ea785922
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1 | f0cbd3ec | bellard | /*
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2 | f0cbd3ec | bellard | * QEMU BOOTP/DHCP server
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3 | f0cbd3ec | bellard | *
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4 | f0cbd3ec | bellard | * Copyright (c) 2004 Fabrice Bellard
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5 | f0cbd3ec | bellard | *
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6 | f0cbd3ec | bellard | * Permission is hereby granted, free of charge, to any person obtaining a copy
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7 | f0cbd3ec | bellard | * of this software and associated documentation files (the "Software"), to deal
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8 | f0cbd3ec | bellard | * in the Software without restriction, including without limitation the rights
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9 | f0cbd3ec | bellard | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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10 | f0cbd3ec | bellard | * copies of the Software, and to permit persons to whom the Software is
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11 | f0cbd3ec | bellard | * furnished to do so, subject to the following conditions:
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12 | f0cbd3ec | bellard | *
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13 | f0cbd3ec | bellard | * The above copyright notice and this permission notice shall be included in
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14 | f0cbd3ec | bellard | * all copies or substantial portions of the Software.
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15 | f0cbd3ec | bellard | *
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16 | f0cbd3ec | bellard | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 | f0cbd3ec | bellard | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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18 | f0cbd3ec | bellard | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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19 | f0cbd3ec | bellard | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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20 | f0cbd3ec | bellard | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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21 | f0cbd3ec | bellard | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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22 | f0cbd3ec | bellard | * THE SOFTWARE.
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23 | f0cbd3ec | bellard | */
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24 | f0cbd3ec | bellard | #include <slirp.h> |
25 | f0cbd3ec | bellard | |
26 | f0cbd3ec | bellard | /* XXX: only DHCP is supported */
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27 | f0cbd3ec | bellard | |
28 | f0cbd3ec | bellard | #define NB_ADDR 16 |
29 | f0cbd3ec | bellard | |
30 | f0cbd3ec | bellard | #define START_ADDR 15 |
31 | f0cbd3ec | bellard | |
32 | f0cbd3ec | bellard | #define LEASE_TIME (24 * 3600) |
33 | f0cbd3ec | bellard | |
34 | f0cbd3ec | bellard | typedef struct { |
35 | f0cbd3ec | bellard | uint8_t allocated; |
36 | 512176db | bellard | uint8_t macaddr[6];
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37 | f0cbd3ec | bellard | } BOOTPClient; |
38 | f0cbd3ec | bellard | |
39 | f0cbd3ec | bellard | BOOTPClient bootp_clients[NB_ADDR]; |
40 | f0cbd3ec | bellard | |
41 | f0cbd3ec | bellard | static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE }; |
42 | f0cbd3ec | bellard | |
43 | f0cbd3ec | bellard | #ifdef DEBUG
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44 | f0cbd3ec | bellard | #define dprintf(fmt, args...) \
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45 | f0cbd3ec | bellard | if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); } |
46 | f0cbd3ec | bellard | #else
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47 | f0cbd3ec | bellard | #define dprintf(fmt, args...)
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48 | f0cbd3ec | bellard | #endif
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49 | f0cbd3ec | bellard | |
50 | f0cbd3ec | bellard | static BOOTPClient *get_new_addr(struct in_addr *paddr) |
51 | f0cbd3ec | bellard | { |
52 | f0cbd3ec | bellard | BOOTPClient *bc; |
53 | f0cbd3ec | bellard | int i;
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54 | f0cbd3ec | bellard | |
55 | f0cbd3ec | bellard | for(i = 0; i < NB_ADDR; i++) { |
56 | f0cbd3ec | bellard | if (!bootp_clients[i].allocated)
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57 | f0cbd3ec | bellard | goto found;
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58 | f0cbd3ec | bellard | } |
59 | f0cbd3ec | bellard | return NULL; |
60 | f0cbd3ec | bellard | found:
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61 | f0cbd3ec | bellard | bc = &bootp_clients[i]; |
62 | f0cbd3ec | bellard | bc->allocated = 1;
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63 | f0cbd3ec | bellard | paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
64 | f0cbd3ec | bellard | return bc;
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65 | f0cbd3ec | bellard | } |
66 | f0cbd3ec | bellard | |
67 | 512176db | bellard | static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr) |
68 | 512176db | bellard | { |
69 | 512176db | bellard | BOOTPClient *bc; |
70 | 512176db | bellard | int i;
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71 | 512176db | bellard | |
72 | 512176db | bellard | for(i = 0; i < NB_ADDR; i++) { |
73 | 512176db | bellard | if (!memcmp(macaddr, bootp_clients[i].macaddr, 6)) |
74 | 512176db | bellard | goto found;
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75 | 512176db | bellard | } |
76 | 512176db | bellard | return NULL; |
77 | 512176db | bellard | found:
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78 | 512176db | bellard | bc = &bootp_clients[i]; |
79 | 512176db | bellard | bc->allocated = 1;
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80 | 512176db | bellard | paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR)); |
81 | 512176db | bellard | return bc;
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82 | 512176db | bellard | } |
83 | 512176db | bellard | |
84 | f0cbd3ec | bellard | static void dhcp_decode(const uint8_t *buf, int size, |
85 | f0cbd3ec | bellard | int *pmsg_type)
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86 | f0cbd3ec | bellard | { |
87 | f0cbd3ec | bellard | const uint8_t *p, *p_end;
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88 | f0cbd3ec | bellard | int len, tag;
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89 | f0cbd3ec | bellard | |
90 | f0cbd3ec | bellard | *pmsg_type = 0;
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91 | f0cbd3ec | bellard | |
92 | f0cbd3ec | bellard | p = buf; |
93 | f0cbd3ec | bellard | p_end = buf + size; |
94 | f0cbd3ec | bellard | if (size < 5) |
95 | f0cbd3ec | bellard | return;
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96 | f0cbd3ec | bellard | if (memcmp(p, rfc1533_cookie, 4) != 0) |
97 | f0cbd3ec | bellard | return;
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98 | f0cbd3ec | bellard | p += 4;
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99 | f0cbd3ec | bellard | while (p < p_end) {
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100 | f0cbd3ec | bellard | tag = p[0];
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101 | f0cbd3ec | bellard | if (tag == RFC1533_PAD) {
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102 | f0cbd3ec | bellard | p++; |
103 | f0cbd3ec | bellard | } else if (tag == RFC1533_END) { |
104 | f0cbd3ec | bellard | break;
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105 | f0cbd3ec | bellard | } else {
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106 | f0cbd3ec | bellard | p++; |
107 | f0cbd3ec | bellard | if (p >= p_end)
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108 | f0cbd3ec | bellard | break;
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109 | f0cbd3ec | bellard | len = *p++; |
110 | f0cbd3ec | bellard | dprintf("dhcp: tag=0x%02x len=%d\n", tag, len);
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111 | f0cbd3ec | bellard | |
112 | f0cbd3ec | bellard | switch(tag) {
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113 | f0cbd3ec | bellard | case RFC2132_MSG_TYPE:
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114 | f0cbd3ec | bellard | if (len >= 1) |
115 | f0cbd3ec | bellard | *pmsg_type = p[0];
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116 | f0cbd3ec | bellard | break;
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117 | f0cbd3ec | bellard | default:
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118 | f0cbd3ec | bellard | break;
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119 | f0cbd3ec | bellard | } |
120 | f0cbd3ec | bellard | p += len; |
121 | f0cbd3ec | bellard | } |
122 | f0cbd3ec | bellard | } |
123 | f0cbd3ec | bellard | } |
124 | f0cbd3ec | bellard | |
125 | f0cbd3ec | bellard | static void bootp_reply(struct bootp_t *bp) |
126 | f0cbd3ec | bellard | { |
127 | f0cbd3ec | bellard | BOOTPClient *bc; |
128 | f0cbd3ec | bellard | struct mbuf *m;
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129 | f0cbd3ec | bellard | struct bootp_t *rbp;
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130 | f0cbd3ec | bellard | struct sockaddr_in saddr, daddr;
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131 | f0cbd3ec | bellard | struct in_addr dns_addr;
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132 | f0cbd3ec | bellard | int dhcp_msg_type, val;
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133 | f0cbd3ec | bellard | uint8_t *q; |
134 | f0cbd3ec | bellard | |
135 | f0cbd3ec | bellard | /* extract exact DHCP msg type */
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136 | f0cbd3ec | bellard | dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type); |
137 | f0cbd3ec | bellard | dprintf("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type);
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138 | f0cbd3ec | bellard | |
139 | 487be8a1 | bellard | if (dhcp_msg_type == 0) |
140 | 487be8a1 | bellard | dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
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141 | 487be8a1 | bellard | |
142 | f0cbd3ec | bellard | if (dhcp_msg_type != DHCPDISCOVER &&
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143 | f0cbd3ec | bellard | dhcp_msg_type != DHCPREQUEST) |
144 | f0cbd3ec | bellard | return;
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145 | f0cbd3ec | bellard | /* XXX: this is a hack to get the client mac address */
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146 | f0cbd3ec | bellard | memcpy(client_ethaddr, bp->bp_hwaddr, 6);
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147 | f0cbd3ec | bellard | |
148 | f0cbd3ec | bellard | if ((m = m_get()) == NULL) |
149 | f0cbd3ec | bellard | return;
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150 | f0cbd3ec | bellard | m->m_data += if_maxlinkhdr; |
151 | f0cbd3ec | bellard | rbp = (struct bootp_t *)m->m_data;
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152 | f0cbd3ec | bellard | m->m_data += sizeof(struct udpiphdr); |
153 | f0cbd3ec | bellard | memset(rbp, 0, sizeof(struct bootp_t)); |
154 | f0cbd3ec | bellard | |
155 | 512176db | bellard | if (dhcp_msg_type == DHCPDISCOVER) {
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156 | d981b883 | bellard | new_addr:
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157 | 512176db | bellard | bc = get_new_addr(&daddr.sin_addr); |
158 | 512176db | bellard | if (!bc) {
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159 | 512176db | bellard | dprintf("no address left\n");
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160 | 512176db | bellard | return;
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161 | 512176db | bellard | } |
162 | 512176db | bellard | memcpy(bc->macaddr, client_ethaddr, 6);
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163 | 512176db | bellard | } else {
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164 | 512176db | bellard | bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr); |
165 | 512176db | bellard | if (!bc) {
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166 | d981b883 | bellard | /* if never assigned, behaves as if it was already
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167 | d981b883 | bellard | assigned (windows fix because it remembers its address) */
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168 | d981b883 | bellard | goto new_addr;
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169 | 512176db | bellard | } |
170 | f0cbd3ec | bellard | } |
171 | f0cbd3ec | bellard | dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr));
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172 | f0cbd3ec | bellard | |
173 | f0cbd3ec | bellard | saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS); |
174 | f0cbd3ec | bellard | saddr.sin_port = htons(BOOTP_SERVER); |
175 | f0cbd3ec | bellard | |
176 | f0cbd3ec | bellard | daddr.sin_port = htons(BOOTP_CLIENT); |
177 | f0cbd3ec | bellard | |
178 | f0cbd3ec | bellard | rbp->bp_op = BOOTP_REPLY; |
179 | f0cbd3ec | bellard | rbp->bp_xid = bp->bp_xid; |
180 | f0cbd3ec | bellard | rbp->bp_htype = 1;
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181 | f0cbd3ec | bellard | rbp->bp_hlen = 6;
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182 | f0cbd3ec | bellard | memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
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183 | f0cbd3ec | bellard | |
184 | e95c8d51 | bellard | rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
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185 | e95c8d51 | bellard | rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
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186 | f0cbd3ec | bellard | |
187 | f0cbd3ec | bellard | q = rbp->bp_vend; |
188 | f0cbd3ec | bellard | memcpy(q, rfc1533_cookie, 4);
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189 | f0cbd3ec | bellard | q += 4;
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190 | f0cbd3ec | bellard | |
191 | f0cbd3ec | bellard | if (dhcp_msg_type == DHCPDISCOVER) {
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192 | f0cbd3ec | bellard | *q++ = RFC2132_MSG_TYPE; |
193 | f0cbd3ec | bellard | *q++ = 1;
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194 | f0cbd3ec | bellard | *q++ = DHCPOFFER; |
195 | f0cbd3ec | bellard | } else if (dhcp_msg_type == DHCPREQUEST) { |
196 | f0cbd3ec | bellard | *q++ = RFC2132_MSG_TYPE; |
197 | f0cbd3ec | bellard | *q++ = 1;
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198 | f0cbd3ec | bellard | *q++ = DHCPACK; |
199 | f0cbd3ec | bellard | } |
200 | f0cbd3ec | bellard | |
201 | f0cbd3ec | bellard | if (dhcp_msg_type == DHCPDISCOVER ||
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202 | f0cbd3ec | bellard | dhcp_msg_type == DHCPREQUEST) { |
203 | f0cbd3ec | bellard | *q++ = RFC2132_SRV_ID; |
204 | f0cbd3ec | bellard | *q++ = 4;
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205 | f0cbd3ec | bellard | memcpy(q, &saddr.sin_addr, 4);
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206 | f0cbd3ec | bellard | q += 4;
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207 | f0cbd3ec | bellard | |
208 | f0cbd3ec | bellard | *q++ = RFC1533_NETMASK; |
209 | f0cbd3ec | bellard | *q++ = 4;
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210 | f0cbd3ec | bellard | *q++ = 0xff;
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211 | f0cbd3ec | bellard | *q++ = 0xff;
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212 | f0cbd3ec | bellard | *q++ = 0xff;
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213 | f0cbd3ec | bellard | *q++ = 0x00;
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214 | f0cbd3ec | bellard | |
215 | f0cbd3ec | bellard | *q++ = RFC1533_GATEWAY; |
216 | f0cbd3ec | bellard | *q++ = 4;
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217 | f0cbd3ec | bellard | memcpy(q, &saddr.sin_addr, 4);
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218 | f0cbd3ec | bellard | q += 4;
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219 | f0cbd3ec | bellard | |
220 | f0cbd3ec | bellard | *q++ = RFC1533_DNS; |
221 | f0cbd3ec | bellard | *q++ = 4;
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222 | f0cbd3ec | bellard | dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS); |
223 | f0cbd3ec | bellard | memcpy(q, &dns_addr, 4);
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224 | f0cbd3ec | bellard | q += 4;
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225 | f0cbd3ec | bellard | |
226 | f0cbd3ec | bellard | *q++ = RFC2132_LEASE_TIME; |
227 | f0cbd3ec | bellard | *q++ = 4;
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228 | f0cbd3ec | bellard | val = htonl(LEASE_TIME); |
229 | f0cbd3ec | bellard | memcpy(q, &val, 4);
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230 | f0cbd3ec | bellard | q += 4;
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231 | 115defd1 | pbrook | |
232 | 115defd1 | pbrook | if (*slirp_hostname) {
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233 | 115defd1 | pbrook | val = strlen(slirp_hostname); |
234 | 115defd1 | pbrook | *q++ = RFC1533_HOSTNAME; |
235 | 115defd1 | pbrook | *q++ = val; |
236 | 115defd1 | pbrook | memcpy(q, slirp_hostname, val); |
237 | 115defd1 | pbrook | q += val; |
238 | 115defd1 | pbrook | } |
239 | f0cbd3ec | bellard | } |
240 | f0cbd3ec | bellard | *q++ = RFC1533_END; |
241 | f0cbd3ec | bellard | |
242 | 44bbf73f | bellard | m->m_len = sizeof(struct bootp_t) - |
243 | 44bbf73f | bellard | sizeof(struct ip) - sizeof(struct udphdr); |
244 | f0cbd3ec | bellard | udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
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245 | f0cbd3ec | bellard | } |
246 | f0cbd3ec | bellard | |
247 | f0cbd3ec | bellard | void bootp_input(struct mbuf *m) |
248 | f0cbd3ec | bellard | { |
249 | 101c5935 | bellard | struct bootp_t *bp = mtod(m, struct bootp_t *); |
250 | f0cbd3ec | bellard | |
251 | f0cbd3ec | bellard | if (bp->bp_op == BOOTP_REQUEST) {
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252 | f0cbd3ec | bellard | bootp_reply(bp); |
253 | f0cbd3ec | bellard | } |
254 | f0cbd3ec | bellard | } |