Commit | Line | Data |
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f1b2fa5b | 1 | /* ip_icmp.c 4.9 81/11/29 */ |
81a36a8d BJ |
2 | |
3 | #include "../h/param.h" | |
2b4b57cd | 4 | #include "../h/systm.h" |
81a36a8d | 5 | #include "../h/mbuf.h" |
cdad2eb1 BJ |
6 | #include "../h/protosw.h" |
7 | #include "../h/clock.h" | |
8a13b737 BJ |
8 | #include "../net/in.h" |
9 | #include "../net/in_systm.h" | |
d52566dd BJ |
10 | #include "../net/ip.h" |
11 | #include "../net/ip_icmp.h" | |
81a36a8d BJ |
12 | |
13 | /* | |
14 | * ICMP routines: error generation, receive packet processing, and | |
15 | * routines to turnaround packets back to the originator, and | |
16 | * host table maintenance routines. | |
17 | */ | |
18 | ||
19 | /* | |
20 | * Generate an error packet of type error in response to bad packet ip. | |
21 | */ | |
22 | icmp_error(oip, type, code) | |
23 | struct ip *oip; | |
24 | int type; | |
25 | { | |
cdad2eb1 | 26 | unsigned oiplen = oip->ip_hl << 2; |
d52566dd | 27 | struct icmp *icp = (struct icmp *)((int)oip + oiplen); |
81a36a8d BJ |
28 | struct mbuf *m; |
29 | struct ip *nip; | |
8a13b737 | 30 | COUNT(ICMP_ERROR); |
81a36a8d BJ |
31 | |
32 | /* | |
33 | * Make sure that the old IP packet had 8 bytes of data to return; | |
34 | * if not, don't bother. Also don't EVER error if the old | |
35 | * packet protocol was ICMP. | |
36 | */ | |
37 | if (oip->ip_len - oiplen < 8 || oip->ip_p == IPPROTO_ICMP) | |
38 | goto free; | |
39 | ||
40 | /* | |
41 | * Get a new mbuf, and fill in a ICMP header at the bottom | |
42 | * of the mbuf, followed by the old IP header and 8 bytes | |
43 | * of its data. | |
44 | */ | |
45 | m = m_get(0); | |
46 | if (m == 0) | |
47 | goto free; | |
48 | m->m_off = MMAXOFF - (oiplen + 8); | |
49 | icp->icmp_type = type; | |
50 | if (type == ICMP_PARAMPROB) { | |
51 | icp->icmp_code = 0; | |
52 | icp->icmp_pptr = code; | |
53 | } else | |
54 | icp->icmp_code = code; | |
d52566dd | 55 | bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, oiplen + 8); |
81a36a8d BJ |
56 | |
57 | /* | |
58 | * Now prepend an IP header and reflect this packet back to | |
59 | * the source. | |
60 | */ | |
61 | m->m_off -= sizeof (struct ip); | |
62 | m->m_len += sizeof (struct ip); | |
d52566dd BJ |
63 | nip = (struct ip *)mtod(m, struct ip *); |
64 | *nip = *oip; | |
65 | icmp_reflect(nip); | |
81a36a8d BJ |
66 | |
67 | /* | |
68 | * Discard mbufs of original datagram | |
69 | */ | |
70 | free: | |
71 | m_freem(dtom(oip)); | |
72 | } | |
73 | ||
74 | /* | |
d52566dd | 75 | * Process a received ICMP message. |
81a36a8d BJ |
76 | */ |
77 | icmp_input(m) | |
78 | struct mbuf *m; | |
79 | { | |
81a36a8d | 80 | register struct icmp *icp; |
d52566dd BJ |
81 | register struct ip *ip = mtod(m, struct ip *); |
82 | int hlen = ip->ip_hl << 2; | |
81a36a8d | 83 | int icmplen = ip->ip_len - hlen; |
d52566dd | 84 | int i; |
8a13b737 | 85 | COUNT(ICMP_INPUT); |
81a36a8d BJ |
86 | |
87 | /* | |
88 | * Locate icmp structure in mbuf, and check | |
89 | * that not corrupted and of at least minimum length. | |
90 | */ | |
91 | m->m_len -= hlen; | |
92 | m->m_off += hlen; | |
93 | /* need routine to make sure header is in this mbuf here */ | |
d52566dd | 94 | icp = (struct icmp *)mtod(m, struct icmp *); |
81a36a8d BJ |
95 | i = icp->icmp_cksum; |
96 | icp->icmp_cksum = 0; | |
8a13b737 | 97 | if (i != in_cksum(m, icmplen) || icmplen < ICMP_MINLEN) |
d52566dd | 98 | goto free; |
81a36a8d BJ |
99 | |
100 | /* | |
101 | * Message type specific processing. | |
102 | */ | |
d52566dd | 103 | switch (icp->icmp_type) { |
81a36a8d BJ |
104 | |
105 | case ICMP_UNREACH: | |
106 | case ICMP_TIMXCEED: | |
107 | case ICMP_PARAMPROB: | |
108 | case ICMP_SOURCEQUENCH: | |
109 | case ICMP_REDIRECT: | |
110 | /* | |
111 | * Problem with previous datagram; advise | |
112 | * higher level routines. | |
113 | */ | |
d52566dd BJ |
114 | if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) |
115 | goto free; | |
cdad2eb1 | 116 | icmp_ctlinput(ip); |
81a36a8d BJ |
117 | goto free; |
118 | ||
119 | case ICMP_ECHO: | |
120 | icp->icmp_type = ICMP_ECHOREPLY; | |
121 | goto reflect; | |
122 | ||
123 | case ICMP_TSTAMP: | |
d52566dd BJ |
124 | if (icmplen < ICMP_TSLEN) |
125 | goto free; | |
81a36a8d | 126 | icp->icmp_type = ICMP_TSTAMPREPLY; |
2b4b57cd | 127 | icp->icmp_rtime = iptime(); |
81a36a8d BJ |
128 | icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ |
129 | goto reflect; | |
130 | ||
131 | case ICMP_IREQ: | |
132 | /* fill in source address zero fields! */ | |
133 | goto reflect; | |
134 | ||
135 | case ICMP_ECHOREPLY: | |
136 | case ICMP_TSTAMPREPLY: | |
137 | case ICMP_IREQREPLY: | |
d52566dd BJ |
138 | if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) |
139 | goto free; | |
81a36a8d BJ |
140 | icmp_gotreply(icp); |
141 | goto free; | |
142 | ||
143 | default: | |
144 | goto free; | |
145 | } | |
146 | reflect: | |
147 | icmp_reflect(ip); | |
148 | free: | |
149 | m_freem(dtom(ip)); | |
150 | } | |
151 | ||
152 | /* | |
153 | * Reflect the ip packet back to the source | |
154 | */ | |
155 | icmp_reflect(ip) | |
156 | struct ip *ip; | |
157 | { | |
2b4b57cd | 158 | struct in_addr t; |
8a13b737 | 159 | COUNT(ICMP_REFLECT); |
81a36a8d | 160 | |
d52566dd | 161 | t = ip->ip_src; ip->ip_dst = ip->ip_src; ip->ip_src = t; |
81a36a8d BJ |
162 | /* |
163 | * This is a little naive... do we have to munge the options | |
164 | * to reverse source routing? | |
165 | */ | |
81a36a8d BJ |
166 | icmp_send(ip); |
167 | } | |
168 | ||
169 | /* | |
170 | * Send an icmp packet back to the ip level, after | |
171 | * supplying a checksum. | |
172 | */ | |
cdad2eb1 | 173 | icmp_send(ip) |
81a36a8d | 174 | struct ip *ip; |
81a36a8d | 175 | { |
cdad2eb1 | 176 | struct icmp *icp = 0; /* XXX */ |
8a13b737 | 177 | COUNT(ICMP_SEND); |
81a36a8d | 178 | |
d52566dd | 179 | icp->icmp_cksum = 0; |
8a13b737 | 180 | icp->icmp_cksum = in_cksum(dtom(ip), 0); /* XXX */ |
4d5fc554 | 181 | ip->ip_ttl = MAXTTL; |
f1b2fa5b | 182 | (void) ip_output(dtom(ip), (struct mbuf *)0); |
81a36a8d BJ |
183 | } |
184 | ||
185 | /* | |
186 | * Advise a higher level protocol of a problem reported by | |
187 | * a gateway or another host. | |
188 | */ | |
cdad2eb1 | 189 | icmp_ctlinput(ip) |
81a36a8d | 190 | struct ip *ip; |
81a36a8d | 191 | { |
cdad2eb1 | 192 | extern u_char ip_protox[]; /* XXX */ |
8a13b737 | 193 | COUNT(ICMP_CTLINPUT); |
81a36a8d | 194 | |
cdad2eb1 | 195 | (*protosw[ip_protox[ip->ip_p]].pr_ctlinput)(ip); |
81a36a8d BJ |
196 | } |
197 | ||
198 | /* | |
199 | * Got a reply, e.g. to an echo message or a timestamp | |
200 | * message; nothing is done with these yet. | |
201 | */ | |
202 | /*ARGSUSED*/ | |
203 | icmp_gotreply(icp) | |
204 | struct icmp *icp; | |
205 | { | |
206 | ||
8a13b737 | 207 | COUNT(ICMP_GOTREPLY); |
81a36a8d | 208 | } |
d52566dd BJ |
209 | |
210 | icmp_drain() | |
211 | { | |
212 | ||
8a13b737 | 213 | COUNT(ICMP_DRAIN); |
d52566dd BJ |
214 | } |
215 | ||
cdad2eb1 | 216 | n_time |
2b4b57cd | 217 | iptime() |
d52566dd | 218 | { |
cdad2eb1 | 219 | int s = spl6(); |
2752c877 | 220 | u_long t; |
d52566dd | 221 | |
8a13b737 | 222 | COUNT(IPTIME); |
cdad2eb1 BJ |
223 | t = (time % SECDAY) * 1000 + lbolt * hz; |
224 | splx(s); | |
225 | return (htonl(t)); | |
d52566dd | 226 | } |