1 /* $OpenBSD: print-null.c,v 1.25 2021/12/01 18:28:46 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 */
23
24 #include <sys/time.h>
25 #include <sys/socket.h>
26 #include <sys/file.h>
27 #include <sys/ioctl.h>
28
29 #include <net/if.h>
30
31 #include <netinet/in.h>
32 #include <netinet/ip.h>
33 #include <netinet/ip6.h>
34 #include <netinet/if_ether.h>
35 #include <netinet/ip_var.h>
36 #include <netinet/udp.h>
37 #include <netinet/udp_var.h>
38 #include <netinet/tcp.h>
39
40 #include <pcap.h>
41 #include <stdio.h>
42 #include <string.h>
43
44 #include "interface.h"
45 #include "addrtoname.h"
46
47 #ifndef AF_NS
48 #define AF_NS 6 /* XEROX NS protocols */
49 #endif
50
51 /*
52 * The DLT_NULL packet header is 4 bytes long. It contains a host
53 * order 32 bit integer that specifies the family, e.g. AF_INET
54 */
55 #define NULL_HDRLEN 4
56
57 static void
null_print(const u_char * p,const struct ip * ip,u_int length)58 null_print(const u_char *p, const struct ip *ip, u_int length)
59 {
60 u_int family;
61
62 memcpy((char *)&family, (char *)p, sizeof(family));
63
64 if (nflag && family != AF_LINK) {
65 /* XXX just dump the header */
66 return;
67 }
68 switch (family) {
69
70 case AF_INET:
71 printf("ip: ");
72 break;
73
74 case AF_INET6:
75 printf("ip6: ");
76 break;
77
78 case AF_NS:
79 printf("ns: ");
80 break;
81
82 #ifdef __OpenBSD__
83 case AF_LINK:
84 ether_print(p + NULL_HDRLEN, length);
85 break;
86 #endif
87 case AF_MPLS:
88 printf("mpls: ");
89 break;
90
91 default:
92 printf("AF %d: ", family);
93 break;
94 }
95 }
96
97 void
loop_if_print(u_char * user,const struct pcap_pkthdr * h,const u_char * p)98 loop_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
99 {
100 *(u_int *)p = ntohl(*(u_int *)p);
101
102 null_if_print(user, h, p);
103 }
104
105 void
null_if_print(u_char * user,const struct pcap_pkthdr * h,const u_char * p)106 null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
107 {
108 u_int length = h->len;
109 u_int caplen = h->caplen;
110 u_int family = *(u_int *)p;
111
112 #ifdef __OpenBSD__
113 struct ether_header *ep;
114 u_short ether_type;
115 extern u_short extracted_ethertype;
116 #endif
117
118 ts_print(&h->ts);
119
120 if (caplen < NULL_HDRLEN) {
121 printf("[|null]");
122 goto out;
123 }
124
125 /*
126 * Some printers want to get back at the link level addresses,
127 * and/or check that they're not walking off the end of the packet.
128 * Rather than pass them all the way down, we set these globals.
129 */
130 packetp = p;
131 snapend = p + caplen;
132
133 length -= NULL_HDRLEN;
134
135 if (eflag)
136 null_print(p, (struct ip *)(p + NULL_HDRLEN), length);
137
138 switch (family) {
139 case AF_INET:
140 ip_print(p + NULL_HDRLEN, length);
141 break;
142
143 case AF_INET6:
144 ip6_print(p + NULL_HDRLEN, length);
145 break;
146
147 case AF_MPLS:
148 mpls_print(p + NULL_HDRLEN, length);
149 break;
150
151 #ifdef __OpenBSD__
152 case AF_LINK:
153 if (caplen < sizeof(struct ether_header) + NULL_HDRLEN) {
154 printf("[|ether]");
155 goto out;
156 }
157
158 length -= sizeof(struct ether_header);
159 caplen -= sizeof(struct ether_header);
160 ep = (struct ether_header *)(p + NULL_HDRLEN);
161 p += NULL_HDRLEN + sizeof(struct ether_header);
162 packetp += sizeof(struct ether_header);
163 ether_type = ntohs(ep->ether_type);
164
165 extracted_ethertype = 0;
166 if (ether_type <= ETHERMTU) {
167 /* Try to print the LLC-layer header & higher layers */
168 if (llc_print(p, length, caplen, ESRC(ep),
169 EDST(ep)) == 0) {
170 /* ether_type not known, print raw packet */
171 if (!eflag)
172 ether_print((u_char *)ep, length);
173 if (extracted_ethertype) {
174 printf("(LLC %s) ",
175 etherproto_string(htons(extracted_ethertype)));
176 }
177 if (!xflag && !qflag)
178 default_print(p, caplen - NULL_HDRLEN);
179 }
180 } else if (ether_encap_print(ether_type, p, length,
181 caplen) == 0) {
182 /* ether_type not known, print raw packet */
183 if (!eflag)
184 ether_print((u_char *)ep, length +
185 sizeof(*ep));
186 if (!xflag && !qflag)
187 default_print(p, caplen - NULL_HDRLEN);
188 }
189 break;
190 #endif /* __OpenBSD__ */
191 }
192
193 if (xflag)
194 default_print((const u_char *)(packetp + NULL_HDRLEN),
195 caplen - NULL_HDRLEN);
196 out:
197 putchar('\n');
198 }
199
200