1 /*
2 * Stanford Enetfilter subroutines for tcpdump
3 *
4 * Based on the MERIT NNstat etherifrt.c and the Ultrix pcap-pf.c
5 * subroutines.
6 *
7 * Rayan Zachariassen, CA*Net
8 */
9
10 #include <config.h>
11
12 #include <sys/types.h>
13 #include <sys/time.h>
14 #include <sys/file.h>
15 #include <sys/ioctl.h>
16 #include <sys/socket.h>
17
18 #include <net/if.h>
19 #include <pcap/bpf.h>
20 #include <net/enet.h>
21
22 #include <netinet/in.h>
23 #include <netinet/if_ether.h>
24
25 #include <stdio.h>
26 #include <errno.h>
27
28 #include "interface.h"
29
30 struct packet_header {
31 #ifdef IBMRTPC
32 struct LengthWords length;
33 struct tap_header tap;
34 #endif /* IBMRTPC */
35 u_char packet[8]
36 };
37
38 extern int errno;
39
40 #define BUFSPACE (4*1024)
41
42 /* Forwards */
43 static void efReadError(int, char *);
44
45 void
readloop(int cnt,int if_fd,struct bpf_program * fp,printfunc printit)46 readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit)
47 {
48 #ifdef IBMRTPC
49 register struct packet_header *ph;
50 register u_char *bp;
51 register int inc;
52 #else /* !IBMRTPC */
53 static struct timeval tv = { 0 };
54 #endif /* IBMRTPC */
55 register int cc, caplen;
56 register struct bpf_insn *fcode = fp->bf_insns;
57 union {
58 struct packet_header hdr;
59 u_char p[BUFSPACE];
60 u_short s;
61 } buf;
62
63 while (1) {
64 if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0)
65 efReadError(if_fd, "reader");
66
67 #ifdef IBMRTPC
68 /*
69 * Loop through each packet.
70 */
71 bp = buf.p;
72 while (cc > 0) {
73 ph = (struct packet_header *)bp;
74 caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap
75 .th_wirelen ;
76 if (pcapint_filter(fcode, (char *)ph->packet,
77 ph->tap.th_wirelen, caplen)) {
78 if (cnt >= 0 && --cnt < 0)
79 goto out;
80 (*printit)((char *)ph->packet,
81 (struct timeval *)ph->tap.th_timestamp,
82 ph->tap.th_wirelen, caplen);
83 }
84 inc = ph->length.PacketOffset;
85 cc -= inc;
86 bp += inc;
87 }
88 #else /* !IBMRTPC */
89 caplen = cc > snaplen ? snaplen : cc ;
90 if (pcapint_filter(fcode, buf.hdr.packet, cc, caplen)) {
91 if (cnt >= 0 && --cnt < 0)
92 goto out;
93 (*printit)(buf.hdr.packet, &tv, cc, caplen);
94 }
95 #endif /* IBMRTPC */
96 }
97 out:
98 wrapup(if_fd);
99 }
100
101 /* Call ONLY if read() has returned an error on packet filter */
102 static void
efReadError(int fid,char * msg)103 efReadError(int fid, char *msg)
104 {
105 if (errno == EINVAL) { /* read MAXINT bytes already! */
106 if (lseek(fid, 0, 0) < 0) {
107 perror("tcpdump: efReadError/lseek");
108 exit(-1);
109 }
110 else
111 return;
112 }
113 else {
114 (void) fprintf(stderr, "tcpdump: ");
115 perror(msg);
116 exit(-1);
117 }
118 }
119
120 void
wrapup(int fd)121 wrapup(int fd)
122 {
123 #ifdef IBMRTPC
124 struct enstats es;
125
126 if (ioctl(fd, EIOSTATS, &es) == -1) {
127 perror("tcpdump: enet ioctl EIOSTATS error");
128 exit(-1);
129 }
130
131 fprintf(stderr, "%d packets queued", es.enStat_Rcnt);
132 if (es.enStat_Rdrops > 0)
133 fprintf(stderr, ", %d dropped", es.enStat_Rdrops);
134 if (es.enStat_Reads > 0)
135 fprintf(stderr, ", %d tcpdump %s", es.enStat_Reads,
136 es.enStat_Reads > 1 ? "reads" : "read");
137 if (es.enStat_MaxRead > 1)
138 fprintf(stderr, ", %d packets in largest read",
139 es.enStat_MaxRead);
140 putc('\n', stderr);
141 #endif /* IBMRTPC */
142 close(fd);
143 }
144
145 int
initdevice(char * device,int pflag,int * linktype)146 initdevice(char *device, int pflag, int *linktype)
147 {
148 struct eniocb ctl;
149 struct enfilter filter;
150 u_int maxwaiting;
151 int if_fd;
152
153 #ifdef IBMRTPC
154 GETENETDEVICE(0, O_RDONLY, &if_fd);
155 #else /* !IBMRTPC */
156 if_fd = open("/dev/enet", O_RDONLY, 0);
157 #endif /* IBMRTPC */
158
159 if (if_fd == -1) {
160 perror("tcpdump: enet open error");
161 error(
162 "your system may not be properly configured; see \"man enet(4)\"");
163 exit(-1);
164 }
165
166 /* Get operating parameters. */
167
168 if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) {
169 perror("tcpdump: enet ioctl EIOCGETP error");
170 exit(-1);
171 }
172
173 /* Set operating parameters. */
174
175 #ifdef IBMRTPC
176 ctl.en_rtout = 1 * ctl.en_hz;
177 ctl.en_tr_etherhead = 1;
178 ctl.en_tap_network = 1;
179 ctl.en_multi_packet = 1;
180 ctl.en_maxlen = BUFSPACE;
181 #else /* !IBMRTPC */
182 ctl.en_rtout = 64; /* randomly picked value for HZ */
183 #endif /* IBMRTPC */
184 if (ioctl(if_fd, EIOCSETP, &ctl) == -1) {
185 perror("tcpdump: enet ioctl EIOCSETP error");
186 exit(-1);
187 }
188
189 /* Flush the receive queue, since we've changed
190 the operating parameters and we otherwise might
191 receive data without headers. */
192
193 if (ioctl(if_fd, EIOCFLUSH) == -1) {
194 perror("tcpdump: enet ioctl EIOCFLUSH error");
195 exit(-1);
196 }
197
198 /* Set the receive queue depth to its maximum. */
199
200 maxwaiting = ctl.en_maxwaiting;
201 if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) {
202 perror("tcpdump: enet ioctl EIOCSETW error");
203 exit(-1);
204 }
205
206 #ifdef IBMRTPC
207 /* Clear statistics. */
208
209 if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) {
210 perror("tcpdump: enet ioctl EIOCLRSTAT error");
211 exit(-1);
212 }
213 #endif /* IBMRTPC */
214
215 /* Set the filter (accept all packets). */
216
217 filter.enf_Priority = 3;
218 filter.enf_FilterLen = 0;
219 if (ioctl(if_fd, EIOCSETF, &filter) == -1) {
220 perror("tcpdump: enet ioctl EIOCSETF error");
221 exit(-1);
222 }
223 /*
224 * "enetfilter" supports only ethernets.
225 */
226 *linktype = DLT_EN10MB;
227
228 return(if_fd);
229 }
230