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Scan /proc/net/dev on Linux regardless of how we get the interface list.

It's a Linuxism, so it's not necessary on other platforms, and is useful
even if we have getifaddrs().
master
Guy Harris 13 years ago
parent fc03e2cbb6
commit 6831a81489
  1. 144
      fad-gifc.c
  2. 170
      pcap-linux.c

@ -122,136 +122,6 @@ struct rtentry; /* declarations in <net/if.h> */
*/
#define MAX_SA_LEN 255
#ifdef HAVE_PROC_NET_DEV
/*
* Get from "/proc/net/dev" all interfaces listed there; if they're
* already in the list of interfaces we have, that won't add another
* instance, but if they're not, that'll add them.
*
* We don't bother getting any addresses for them; it appears you can't
* use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
* although some other types of addresses can be fetched with SIOCGIFADDR,
* we don't bother with them for now.
*
* We also don't fail if we couldn't open "/proc/net/dev"; we just leave
* the list of interfaces as is.
*/
static int
scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
{
FILE *proc_net_f;
char linebuf[512];
int linenum;
unsigned char *p;
char name[512]; /* XXX - pick a size */
char *q, *saveq;
struct ifreq ifrflags;
int ret = 0;
proc_net_f = fopen("/proc/net/dev", "r");
if (proc_net_f == NULL)
return (0);
for (linenum = 1;
fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
/*
* Skip the first two lines - they're headers.
*/
if (linenum <= 2)
continue;
p = &linebuf[0];
/*
* Skip leading white space.
*/
while (*p != '\0' && isspace(*p))
p++;
if (*p == '\0' || *p == '\n')
continue; /* blank line */
/*
* Get the interface name.
*/
q = &name[0];
while (*p != '\0' && !isspace(*p)) {
if (*p == ':') {
/*
* This could be the separator between a
* name and an alias number, or it could be
* the separator between a name with no
* alias number and the next field.
*
* If there's a colon after digits, it
* separates the name and the alias number,
* otherwise it separates the name and the
* next field.
*/
saveq = q;
while (isdigit(*p))
*q++ = *p++;
if (*p != ':') {
/*
* That was the next field,
* not the alias number.
*/
q = saveq;
}
break;
} else
*q++ = *p++;
}
*q = '\0';
/*
* Get the flags for this interface, and skip it if
* it's not up.
*/
strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
if (errno == ENXIO)
continue;
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFFLAGS: %.*s: %s",
(int)sizeof(ifrflags.ifr_name),
ifrflags.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
if (!(ifrflags.ifr_flags & IFF_UP))
continue;
/*
* Add an entry for this interface, with no addresses.
*/
if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
errbuf) == -1) {
/*
* Failure.
*/
ret = -1;
break;
}
}
if (ret != -1) {
/*
* Well, we didn't fail for any other reason; did we
* fail due to an error reading the file?
*/
if (ferror(proc_net_f)) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"Error reading /proc/net/dev: %s",
pcap_strerror(errno));
ret = -1;
}
}
(void)fclose(proc_net_f);
return (ret);
}
#endif /* HAVE_PROC_NET_DEV */
/*
* Get a list of all interfaces that are up and that we can open.
* Returns -1 on error, 0 otherwise.
@ -537,20 +407,6 @@ pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
}
}
free(buf);
#ifdef HAVE_PROC_NET_DEV
if (ret != -1) {
/*
* We haven't had any errors yet; now read "/proc/net/dev",
* and add to the list of interfaces all interfaces listed
* there that we don't already have, because, on Linux,
* SIOCGIFCONF reports only interfaces with IPv4 addresses,
* so you need to read "/proc/net/dev" to get the names of
* the rest of the interfaces.
*/
ret = scan_proc_net_dev(&devlist, fd, errbuf);
}
#endif
(void)close(fd);
if (ret != -1) {

@ -1774,6 +1774,148 @@ pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
return 0;
}
#ifdef HAVE_PROC_NET_DEV
/*
* Get from "/proc/net/dev" all interfaces listed there; if they're
* already in the list of interfaces we have, that won't add another
* instance, but if they're not, that'll add them.
*
* We don't bother getting any addresses for them; it appears you can't
* use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
* although some other types of addresses can be fetched with SIOCGIFADDR,
* we don't bother with them for now.
*
* We also don't fail if we couldn't open "/proc/net/dev"; we just leave
* the list of interfaces as is.
*/
static int
scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf)
{
FILE *proc_net_f;
int fd;
char linebuf[512];
int linenum;
unsigned char *p;
char name[512]; /* XXX - pick a size */
char *q, *saveq;
struct ifreq ifrflags;
int ret = 0;
proc_net_f = fopen("/proc/net/dev", "r");
if (proc_net_f == NULL)
return (0);
/*
* Create a socket from which to fetch interface information.
*/
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"socket: %s", pcap_strerror(errno));
return (-1);
}
for (linenum = 1;
fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
/*
* Skip the first two lines - they're headers.
*/
if (linenum <= 2)
continue;
p = &linebuf[0];
/*
* Skip leading white space.
*/
while (*p != '\0' && isspace(*p))
p++;
if (*p == '\0' || *p == '\n')
continue; /* blank line */
/*
* Get the interface name.
*/
q = &name[0];
while (*p != '\0' && !isspace(*p)) {
if (*p == ':') {
/*
* This could be the separator between a
* name and an alias number, or it could be
* the separator between a name with no
* alias number and the next field.
*
* If there's a colon after digits, it
* separates the name and the alias number,
* otherwise it separates the name and the
* next field.
*/
saveq = q;
while (isdigit(*p))
*q++ = *p++;
if (*p != ':') {
/*
* That was the next field,
* not the alias number.
*/
q = saveq;
}
break;
} else
*q++ = *p++;
}
*q = '\0';
/*
* Get the flags for this interface, and skip it if
* it's not up.
*/
strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
if (errno == ENXIO)
continue;
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"SIOCGIFFLAGS: %.*s: %s",
(int)sizeof(ifrflags.ifr_name),
ifrflags.ifr_name,
pcap_strerror(errno));
ret = -1;
break;
}
if (!(ifrflags.ifr_flags & IFF_UP))
continue;
/*
* Add an entry for this interface, with no addresses.
*/
if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
errbuf) == -1) {
/*
* Failure.
*/
ret = -1;
break;
}
}
if (ret != -1) {
/*
* Well, we didn't fail for any other reason; did we
* fail due to an error reading the file?
*/
if (ferror(proc_net_f)) {
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
"Error reading /proc/net/dev: %s",
pcap_strerror(errno));
ret = -1;
}
}
(void)close(fd);
(void)fclose(proc_net_f);
return (ret);
}
#endif /* HAVE_PROC_NET_DEV */
/*
* Description string for the "any" device.
*/
@ -1782,25 +1924,53 @@ static const char any_descr[] = "Pseudo-device that captures on all interfaces";
int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
#ifdef HAVE_PROC_NET_DEV
/*
* Read "/proc/net/dev", and add to the list of interfaces all
* interfaces listed there that we don't already have, because,
* on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
* and even getifaddrs() won't return information about
* interfaces with no addresses, so you need to read "/proc/net/dev"
* to get the names of the rest of the interfaces.
*/
if (scan_proc_net_dev(alldevsp, errbuf) == -1)
return (-1);
#endif
/*
* Add the "any" device.
*/
if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0)
return (-1);
#ifdef HAVE_DAG_API
/*
* Add DAG devices.
*/
if (dag_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif /* HAVE_DAG_API */
#ifdef HAVE_SEPTEL_API
/*
* Add Septel devices.
*/
if (septel_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif /* HAVE_SEPTEL_API */
#ifdef PCAP_SUPPORT_BT
/*
* Add Bluetooth devices.
*/
if (bt_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif
#ifdef PCAP_SUPPORT_USB
/*
* Add USB devices.
*/
if (usb_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif