diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/if_index.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/if_index.c | 83 |
1 files changed, 81 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c index 9634aa794f..d2951c6fe1 100644 --- a/sysdeps/unix/sysv/linux/if_index.c +++ b/sysdeps/unix/sysv/linux/if_index.c @@ -54,9 +54,9 @@ opensock (void) if (fd == -1) { - fd = __socket (sock_af = AF_INET6, SOCK_DGRAM, 0); + fd = __socket (sock_af = AF_INET, SOCK_DGRAM, 0); if (fd < 0) - fd = __socket (sock_af = AF_INET, SOCK_DGRAM, 0); + fd = __socket (sock_af = AF_INET6, SOCK_DGRAM, 0); if (fd < 0) fd = __socket (sock_af = AF_IPX, SOCK_DGRAM, 0); if (fd < 0) @@ -277,3 +277,82 @@ if_indextoname (unsigned int ifindex, char *ifname) # endif #endif } + + +void +internal_function +__protocol_avaliable (int *have_inet, int *have_inet6) +{ + int fd = opensock (); + unsigned int nifs; + int rq_len; + struct ifconf ifc; +# if __ASSUME_SIOCGIFNAME == 0 + static int old_siocgifconf; +# else +# define old_siocgifconf 0 +# endif +# define RQ_IFS 4 + + /* Wirst case assumption. */ + *have_inet = 0; + *have_inet6 = 0; + + if (fd == NULL) + /* We cannot open the socket. No networking at all? */ + return; + + /* We may be able to get the needed buffer size directly, rather than + guessing. */ + if (! old_siocgifconf) + { + ifc.ifc_buf = NULL; + ifc.ifc_len = 0; + if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0 || ifc.ifc_len == 0) + { +# if __ASSUME_SIOCGIFNAME == 0 + old_siocgifconf = 1; +# endif + rq_len = RQ_IFS * sizeof (struct ifreq); + } + else + rq_len = ifc.ifc_len; + } + else + rq_len = RQ_IFS * sizeof (struct ifreq); + + /* Read all the interfaces out of the kernel. */ + do + { + ifc.ifc_buf = alloca (ifc.ifc_len = rq_len); + if (ifc.ifc_buf == NULL || __ioctl (fd, SIOCGIFCONF, &ifc) < 0) + { + __close (fd); + return; + } + rq_len *= 2; + } + while (ifc.ifc_len == rq_len && old_siocgifconf); + + nifs = ifc.ifc_len / sizeof (struct ifreq); + + /* Go through all the interfaces and get the address. */ + while (nifs-- > 0) + if (__ioctl (fd, SIOCGIFADDR, &ifc.ifc_req[nifs]) >= 0) + { + /* We successfully got information about this interface. Now + test whether it is an IPv4 or IPv6 address. */ + if (ifc.ifc_req[nifs].ifr_addr.sa_family == AF_INET) + *have_inet = 1; + else if (ifc.ifc_req[nifs].ifr_addr.sa_family == AF_INET6) + *have_inet6 = 1; + + /* Note, this is & not &&. It works since the values are always + 0 or 1. */ + if (*have_inet & *have_inet6) + /* We can stop early. */ + break; + } + + __close (fd); +} |