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1 /*
2  * pcap-septel.c: Packet capture interface for Intel/Septel card.
3  *
4  * The functionality of this code attempts to mimic that of pcap-linux as much
5  * as possible.  This code is compiled in several different ways depending on
6  * whether SEPTEL_ONLY and HAVE_SEPTEL_API are defined.  If HAVE_SEPTEL_API is
7  * not defined it should not get compiled in, otherwise if SEPTEL_ONLY is
8  * defined then the 'septel_' function calls are renamed to 'pcap_'
9  * equivalents.  If SEPTEL_ONLY is not defined then nothing is altered - the
10  * septel_ functions will be called as required from their
11  * pcap-linux/equivalents.
12  *
13  * Authors: Gilbert HOYEK (gil_hoyek@hotmail.com), Elias M. KHOURY
14  * (+961 3 485243)
15  */
16 
17 #ifdef HAVE_CONFIG_H
18 #include "config.h"
19 #endif
20 
21 #include <sys/param.h>
22 
23 #include <stdlib.h>
24 #include <string.h>
25 #include <errno.h>
26 
27 #include "pcap-int.h"
28 
29 #include <ctype.h>
30 #include <netinet/in.h>
31 #include <sys/mman.h>
32 #include <sys/socket.h>
33 #include <sys/types.h>
34 #include <unistd.h>
35 
36 #include <msg.h>
37 #include <ss7_inc.h>
38 #include <sysgct.h>
39 #include <pack.h>
40 #include <system.h>
41 
42 #include "pcap-septel.h"
43 
44 static int septel_setfilter(pcap_t *p, struct bpf_program *fp);
45 static int septel_stats(pcap_t *p, struct pcap_stat *ps);
46 static int septel_setnonblock(pcap_t *p, int nonblock, char *errbuf);
47 
48 /*
49  * Private data for capturing on Septel devices.
50  */
51 struct pcap_septel {
52 	struct pcap_stat stat;
53 }
54 
55 /*
56  *  Read at most max_packets from the capture queue and call the callback
57  *  for each of them. Returns the number of packets handled, -1 if an
58  *  error occured, or -2 if we were told to break out of the loop.
59  */
septel_read(pcap_t * p,int cnt,pcap_handler callback,u_char * user)60 static int septel_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) {
61 
62   struct pcap_septel *ps = p->priv;
63   HDR *h;
64   MSG *m;
65   int processed = 0 ;
66   int t = 0 ;
67 
68   /* identifier for the message queue of the module(upe) from which we are capturing
69    * packets.These IDs are defined in system.txt . By default it is set to 0x2d
70    * so change it to 0xdd for technical reason and therefore the module id for upe becomes:
71    * LOCAL        0xdd           * upe - Example user part task */
72   unsigned int id = 0xdd;
73 
74   /* process the packets */
75   do  {
76 
77     unsigned short packet_len = 0;
78     int caplen = 0;
79     int counter = 0;
80     struct pcap_pkthdr   pcap_header;
81     u_char *dp ;
82 
83     /*
84      * Has "pcap_breakloop()" been called?
85      */
86 loop:
87     if (p->break_loop) {
88       /*
89        * Yes - clear the flag that indicates that
90        * it has, and return -2 to indicate that
91        * we were told to break out of the loop.
92        */
93       p->break_loop = 0;
94       return -2;
95     }
96 
97     /*repeat until a packet is read
98      *a NULL message means :
99      * when no packet is in queue or all packets in queue already read */
100     do  {
101       /* receive packet in non-blocking mode
102        * GCT_grab is defined in the septel library software */
103       h = GCT_grab(id);
104 
105       m = (MSG*)h;
106       /* a couter is added here to avoid an infinite loop
107        * that will cause our capture program GUI to freeze while waiting
108        * for a packet*/
109       counter++ ;
110 
111     }
112     while  ((m == NULL)&& (counter< 100)) ;
113 
114     if (m != NULL) {
115 
116       t = h->type ;
117 
118       /* catch only messages with type = 0xcf00 or 0x8f01 corrsponding to ss7 messages*/
119       /* XXX = why not use API_MSG_TX_REQ for 0xcf00 and API_MSG_RX_IND
120        * for 0x8f01? */
121       if ((t != 0xcf00) && (t != 0x8f01)) {
122         relm(h);
123         goto loop ;
124       }
125 
126       /* XXX - is API_MSG_RX_IND for an MTP2 or MTP3 message? */
127       dp = get_param(m);/* get pointer to MSG parameter area (m->param) */
128       packet_len = m->len;
129       caplen =  p->snapshot ;
130 
131 
132       if (caplen > packet_len) {
133 
134         caplen = packet_len;
135       }
136       /* Run the packet filter if there is one. */
137       if ((p->fcode.bf_insns == NULL) || bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen)) {
138 
139 
140         /*  get a time stamp , consisting of :
141          *
142          *  pcap_header.ts.tv_sec:
143          *  ----------------------
144          *   a UNIX format time-in-seconds when he packet was captured,
145          *   i.e. the number of seconds since Epoch time (January 1,1970, 00:00:00 GMT)
146          *
147          *  pcap_header.ts.tv_usec :
148          *  ------------------------
149          *   the number of microseconds since that second
150          *   when the packet was captured
151          */
152 
153         (void)gettimeofday(&pcap_header.ts, NULL);
154 
155         /* Fill in our own header data */
156         pcap_header.caplen = caplen;
157         pcap_header.len = packet_len;
158 
159         /* Count the packet. */
160         ps->stat.ps_recv++;
161 
162         /* Call the user supplied callback function */
163         callback(user, &pcap_header, dp);
164 
165         processed++ ;
166 
167       }
168       /* after being processed the packet must be
169        *released in order to receive another one */
170       relm(h);
171     }else
172       processed++;
173 
174   }
175   while (processed < cnt) ;
176 
177   return processed ;
178 }
179 
180 
181 static int
septel_inject(pcap_t * handle,const void * buf _U_,size_t size _U_)182 septel_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
183 {
184   strlcpy(handle->errbuf, "Sending packets isn't supported on Septel cards",
185           PCAP_ERRBUF_SIZE);
186   return (-1);
187 }
188 
189 /*
190  *  Activate a handle for a live capture from the given Septel device.  Always pass a NULL device
191  *  The promisc flag is ignored because Septel cards have built-in tracing.
192  *  The timeout is also ignored as it is not supported in hardware.
193  *
194  *  See also pcap(3).
195  */
septel_activate(pcap_t * handle)196 static pcap_t *septel_activate(pcap_t* handle) {
197   /* Initialize some components of the pcap structure. */
198   handle->linktype = DLT_MTP2;
199 
200   handle->bufsize = 0;
201 
202   /*
203    * "select()" and "poll()" don't work on Septel queues
204    */
205   handle->selectable_fd = -1;
206 
207   handle->read_op = septel_read;
208   handle->inject_op = septel_inject;
209   handle->setfilter_op = septel_setfilter;
210   handle->set_datalink_op = NULL; /* can't change data link type */
211   handle->getnonblock_op = pcap_getnonblock_fd;
212   handle->setnonblock_op = septel_setnonblock;
213   handle->stats_op = septel_stats;
214 
215   return 0;
216 }
217 
septel_create(const char * device,char * ebuf,int * is_ours)218 pcap_t *septel_create(const char *device, char *ebuf, int *is_ours) {
219 	const char *cp;
220 	pcap_t *p;
221 
222 	/* Does this look like the Septel device? */
223 	cp = strrchr(device, '/');
224 	if (cp == NULL)
225 		cp = device;
226 	if (strcmp(cp, "septel") != 0) {
227 		/* Nope, it's not "septel" */
228 		*is_ours = 0;
229 		return NULL;
230 	}
231 
232 	/* OK, it's probably ours. */
233 	*is_ours = 1;
234 
235 	p = pcap_create_common(ebuf, sizeof (struct pcap_septel));
236 	if (p == NULL)
237 		return NULL;
238 
239 	p->activate_op = septel_activate;
240 	return p;
241 }
242 
septel_stats(pcap_t * p,struct pcap_stat * ps)243 static int septel_stats(pcap_t *p, struct pcap_stat *ps) {
244   struct pcap_septel *handlep = p->priv;
245   /*handlep->stat.ps_recv = 0;*/
246   /*handlep->stat.ps_drop = 0;*/
247 
248   *ps = handlep->stat;
249 
250   return 0;
251 }
252 
253 
254 int
septel_findalldevs(pcap_if_t ** devlistp,char * errbuf)255 septel_findalldevs(pcap_if_t **devlistp, char *errbuf)
256 {
257   return (pcap_add_if(devlistp,"septel",0,
258                       "Intel/Septel device",errbuf));
259 }
260 
261 
262 /*
263  * Installs the given bpf filter program in the given pcap structure.  There is
264  * no attempt to store the filter in kernel memory as that is not supported
265  * with Septel cards.
266  */
septel_setfilter(pcap_t * p,struct bpf_program * fp)267 static int septel_setfilter(pcap_t *p, struct bpf_program *fp) {
268   if (!p)
269     return -1;
270   if (!fp) {
271     strncpy(p->errbuf, "setfilter: No filter specified",
272 	    sizeof(p->errbuf));
273     return -1;
274   }
275 
276   /* Make our private copy of the filter */
277 
278   if (install_bpf_program(p, fp) < 0) {
279     pcap_snprintf(p->errbuf, sizeof(p->errbuf),
280 	     "malloc: %s", pcap_strerror(errno));
281     return -1;
282   }
283 
284   return (0);
285 }
286 
287 
288 static int
septel_setnonblock(pcap_t * p,int nonblock,char * errbuf)289 septel_setnonblock(pcap_t *p, int nonblock, char *errbuf)
290 {
291   fprintf(errbuf, PCAP_ERRBUF_SIZE, "Non-blocking mode not supported on Septel devices");
292   return (-1);
293 }
294 
295 #ifdef SEPTEL_ONLY
296 /*
297  * This libpcap build supports only Septel cards, not regular network
298  * interfaces.
299  */
300 
301 /*
302  * There are no regular interfaces, just Septel interfaces.
303  */
304 int
pcap_platform_finddevs(pcap_if_t ** alldevsp,char * errbuf)305 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
306 {
307   *alldevsp = NULL;
308   return (0);
309 }
310 
311 /*
312  * Attempts to open a regular interface fail.
313  */
314 pcap_t *
pcap_create_interface(const char * device,char * errbuf)315 pcap_create_interface(const char *device, char *errbuf)
316 {
317   pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
318                 "This version of libpcap only supports Septel cards");
319   return (NULL);
320 }
321 #endif
322