diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/if_index.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/if_index.c | 217 |
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; } |