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path: root/sysdeps/unix/sysv/linux/if_index.c
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Diffstat (limited to 'sysdeps/unix/sysv/linux/if_index.c')
-rw-r--r--sysdeps/unix/sysv/linux/if_index.c217
1 files changed, 127 insertions, 90 deletions
diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
index fc3bd3324f..41bd0535c9 100644
--- a/sysdeps/unix/sysv/linux/if_index.c
+++ b/sysdeps/unix/sysv/linux/if_index.c
@@ -20,121 +20,158 @@
#include <stdio.h>
#include <stdlib.h>
#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <bits/libc-lock.h>
-#define IF_INET6_FILENAME "/proc/net/if_inet6"
-
-/* /proc/net/if_inet6 contains lines that look like this:
- *
- * fe8000000000000000000000836fc168 0b 00 20 80 sit7
- *
- * | | | | | |
- * address --' | | | | |
- * index --------' | | | |
- * prefix length ---' | | |
- * scope --------------' | |
- * flags -----------------' |
- * name -------------------------'
- *
- */
-
-static int get_one_interface(FILE *fd, char *interface, int iflen, unsigned int *index)
+/* Try to get a socket to talk to the kernel. */
+static int
+opensock (void)
{
- char buffer[80];
- static char seps[] = " \012";
- char *c = buffer;
- char *sp;
- if (!fgets(buffer, 80, fd))
- return 1;
- if (strtok_r(buffer, seps, &sp) == NULL) return 1;
- if (c = strtok_r(NULL, seps, &sp), c == NULL) return 1;
- *index = strtoul(c, NULL, 16);
- if (strtok_r(NULL, seps, &sp) == NULL) return 1;
- if (strtok_r(NULL, seps, &sp) == NULL) return 1;
- if (strtok_r(NULL, seps, &sp) == NULL) return 1;
- if (c = strtok_r(NULL, seps, &sp), c == NULL) return 1;
- strncpy(interface, c, iflen);
- return 0;
-}
+ /* Cache the last AF that worked, to avoid many redundant calls to
+ socket(). */
+ static int sock_af = -1;
+ int fd = -1;
+ __libc_lock_define_initialized (static, lock);
-unsigned int if_nametoindex(const char *ifname)
-{
- FILE *fd = fopen(IF_INET6_FILENAME, "r");
- char this_ifname[IFNAMSIZ];
- unsigned int this_index;
- if (!fd) return 0;
- while (get_one_interface(fd, this_ifname, IFNAMSIZ, &this_index) == 0) {
- if (!strcmp(this_ifname, ifname)) {
- fclose(fd);
- return this_index;
+ if (sock_af != -1)
+ {
+ fd = socket (sock_af, SOCK_DGRAM, 0);
+ if (fd != -1)
+ return fd;
+ }
+
+ __libc_lock_lock (lock);
+
+ if (sock_af != -1)
+ fd = socket (sock_af, SOCK_DGRAM, 0);
+
+ if (fd == -1)
+ {
+ fd = socket (sock_af = AF_INET6, SOCK_DGRAM, 0);
+ if (fd < 0)
+ fd = socket (sock_af = AF_INET, SOCK_DGRAM, 0);
+ if (fd < 0)
+ fd = socket (sock_af = AF_IPX, SOCK_DGRAM, 0);
+ if (fd < 0)
+ fd = socket (sock_af = AF_AX25, SOCK_DGRAM, 0);
+ if (fd < 0)
+ fd = socket (sock_af = AF_APPLETALK, SOCK_DGRAM, 0);
}
- }
- fclose(fd);
- return 0;
+
+ __libc_lock_unlock (lock);
+ return fd;
}
-char *if_indextoname(unsigned int ifindex, char *ifname)
+unsigned int
+if_nametoindex (const char *ifname)
{
- FILE *fd = fopen(IF_INET6_FILENAME, "r");
- unsigned int this_index;
- if (!fd) return NULL;
- while (get_one_interface(fd, ifname, IFNAMSIZ, &this_index) == 0) {
- if (this_index == ifindex) {
- fclose(fd);
- return ifname;
+ struct ifreq ifr;
+ int fd = opensock ();
+
+ if (fd < 0)
+ return 0;
+
+ strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
+ if (ioctl (fd, SIOGIFINDEX, &ifr) < 0)
+ {
+ close (fd);
+ return 0;
}
- }
- fclose(fd);
- return NULL;
+ close (fd);
+ return ifr.ifr_ifindex;
}
-void if_freenameindex(struct if_nameindex *ifn)
+void
+if_freenameindex (struct if_nameindex *ifn)
{
struct if_nameindex *ptr = ifn;
while (ptr->if_name || ptr->if_index)
{
if (ptr->if_name)
- free(ptr->if_name);
- ptr++;
+ free (ptr->if_name);
+ ++ptr;
}
- free(ifn);
+ free (ifn);
}
-struct if_nameindex *if_nameindex(void)
+struct if_nameindex *
+if_nameindex (void)
{
- FILE *fd = fopen(IF_INET6_FILENAME, "r");
- struct if_nameindex *ifn = NULL;
- int nifs = 0;
- if (!fd) return NULL;
+ int fd = opensock ();
+ struct ifconf ifc;
+ unsigned int rq_ifs = 4, nifs, i;
+ struct if_nameindex *idx = NULL;
+
+ if (fd < 0)
+ return NULL;
+
+ ifc.ifc_buf = NULL;
+
+ /* Read all the interfaces out of the kernel. */
do
{
- struct if_nameindex *newifn;
- nifs++;
- newifn = realloc(ifn, nifs*sizeof(struct if_nameindex));
- if (!newifn)
+ rq_ifs *= 2;
+ ifc.ifc_len = rq_ifs * sizeof (struct ifreq);
+ ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
+ if (ifc.ifc_buf == NULL)
{
- /* We ran out of memory. */
- if (--nifs)
- {
- free(ifn[nifs-1].if_name);
- ifn[nifs-1].if_name = 0;
- ifn[nifs-1].if_index = 0;
- if_freenameindex(ifn);
- }
+ close(fd);
return NULL;
}
- ifn = newifn;
- ifn[nifs-1].if_index = 0;
- ifn[nifs-1].if_name = malloc(IFNAMSIZ);
- if (ifn[nifs-1].if_name == NULL)
+ if (ioctl (fd, SIOCGIFCONF, &ifc) < 0)
+ goto jump;
+ }
+ while ((unsigned int) ifc.ifc_len == (rq_ifs * sizeof (struct ifreq)));
+
+ nifs = ifc.ifc_len / sizeof (struct ifreq);
+ ifc.ifc_buf = realloc (ifc.ifc_buf, ifc.ifc_len);
+
+ idx = malloc ((nifs+1) * sizeof (struct if_nameindex));
+ if (idx == NULL)
+ goto jump;
+
+ for (i = 0; i < nifs; ++i)
+ {
+ struct ifreq *ifr = &ifc.ifc_req[i];
+ if ((idx[i].if_name = malloc (strlen (ifr->ifr_name)+1)) == NULL)
{
- if_freenameindex(ifn);
- return NULL;
+ free (idx);
+ idx = NULL;
+ goto jump;
+ }
+ strcpy (idx[i].if_name, ifr->ifr_name);
+ if (ioctl (fd, SIOGIFINDEX, ifr) < 0)
+ {
+ free (idx);
+ idx = NULL;
+ goto jump;
}
+ idx[i].if_index = ifr->ifr_ifindex;
}
- while (get_one_interface(fd, ifn[nifs-1].if_name, IFNAMSIZ,
- &ifn[nifs-1].if_index) == 0);
- free(ifn[nifs-1].if_name);
- ifn[nifs-1].if_name = NULL;
- fclose(fd);
- return ifn;
+ idx[i].if_index = 0;
+ idx[i].if_name = NULL;
+
+jump:
+ free (ifc.ifc_buf);
+ close (fd);
+ return idx;
+}
+
+char *
+if_indextoname (unsigned int ifindex, char *ifname)
+{
+ struct if_nameindex *idx = if_nameindex ();
+ struct if_nameindex *p;
+
+ for (p = idx; p->if_index || p->if_name; ++p)
+ if (p->if_index == ifindex)
+ {
+ strncpy (ifname, p->if_name, IFNAMSIZ);
+ if_freenameindex (idx);
+ return ifname;
+ }
+
+ if_freenameindex (idx);
+ return NULL;
}