diff --git a/tools/findif.c b/tools/findif.c index a25395fec..ab108a3c4 100644 --- a/tools/findif.c +++ b/tools/findif.c @@ -1,845 +1,845 @@ /* * findif.c: Finds an interface which can route a given address * * It's really simple to write in C, but hard to write in the shell... * * This code is dependent on IPV4 addressing conventions... * Sorry. * * Copyright (C) 2000 Alan Robertson * Copyright (C) 2001 Matt Soffen * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * *********************************************************** * * All our arguments come through the environment as OCF * environment variables as below: * * OCF_RESKEY_ip * OCF_RESKEY_broadcast * OCF_RESKEY_nic * OCF_RESKEY_cidr_netmask * * If the CIDR netmask is omitted, we choose the netmask associated with * the route we selected. * * If the broadcast address was omitted, we assume the highest address * in the subnet. * * If the interface is omitted, we choose the interface associated with * the route we selected. * * * See http://www.doom.net/docs/netmask.html for a table explaining * CIDR address format and their relationship to life, the universe * and everything. * */ #include #include #include #include #include #include #include #include #ifdef HAVE_SYS_SOCKET_H #include #endif #ifdef HAVE_SYS_SOCKIO_H #include #endif #include #include #include #ifdef __linux__ #undef __OPTIMIZE__ /* * This gets rid of some silly -Wtraditional warnings on Linux * because the netinet header has some slightly funky constants * in it. */ #endif /* __linux__ */ #include #include #include #include #define DEBUG 0 #define EOS '\0' #define PROCROUTE "/proc/net/route" #define ROUTEPARM "-n get" #ifndef HAVE_STRNLEN /* Any system that don't provide strnlen() only has itself to blame */ #define strnlen(str, max) strlen(str) #endif /* * "route -n get iii.jjj.kkk.lll" can, on Solaris at least, * return the word "default" as the value from "mask" and "dest", * typically if the host is remote, reached over a default route. * We should probably treat such a mask as "0.0.0.0". * * Define "MASK_DEFAULT_TO_ZERO" to enable this interpretation. * * This is better for Solaris and is probably suitable (or irrelevant) * for others OSes also. But if it breaks another OS, then reduce the * "hash-if 1" below to exclude that OS. * (David Lee, Jan 2006) */ #if 1 # define MASK_DEFAULT_TO_ZERO #endif static int OutputInCIDR=0; /* * Different OSes offer different mechnisms to obtain this information. * Not all this can be determined at configure-time; need a run-time element. * * typedef ... SearchRoute ...: * For routines that interface on these mechanisms. * Return code: * <0: mechanism invalid, so try next mechanism * 0: mechanism worked: good answer * >0: mechanism worked: bad answer * On non-zero, errmsg may have been filled with an error message */ typedef int SearchRoute (char *address, struct in_addr *in , struct in_addr *addr_out, char *best_if, size_t best_iflen , unsigned long *best_netmask, char *errmsg , int errmsglen); static SearchRoute SearchUsingProcRoute; static SearchRoute SearchUsingRouteCmd; static SearchRoute *search_mechs[] = { &SearchUsingProcRoute, &SearchUsingRouteCmd, NULL }; void GetAddress (char **address, char **netmaskbits , char **bcast_arg, char **if_specified); int ConvertNetmaskBitsToInt(char *netmaskbits); void ValidateNetmaskBits(int bits, unsigned long *netmask); int ValidateIFName (const char *ifname, struct ifreq *ifr); int netmask_bits (unsigned long netmask); char * get_first_loopback_netdev(char * ifname); int is_loopback_interface(char * ifname); char * get_ifname(char * buf, char * ifname); int ConvertQuadToInt(char *dest); static const char *cmdname = "findif"; #define OCF_SUCCESS 0 #define OCF_ERR_GENERIC 1 #define OCF_ERR_ARGS 2 #define OCF_ERR_UNIMPLEMENTED 3 #define OCF_ERR_PERM 4 #define OCF_ERR_INSTALLED 5 #define OCF_ERR_CONFIGURED 6 #define OCF_NOT_RUNNING 7 void usage(int ec); #define PATH_PROC_NET_DEV "/proc/net/dev" #define DELIM '/' #define BAD_BROADCAST (0L) #define MAXSTR 128 static int SearchUsingProcRoute (char *address, struct in_addr *in , struct in_addr *addr_out, char *best_if, size_t best_iflen , unsigned long *best_netmask , char *errmsg, int errmsglen) { unsigned long flags, refcnt, use, gw, mask; unsigned long dest; long metric = LONG_MAX; long best_metric = LONG_MAX; int rc = OCF_SUCCESS; char buf[2048]; char interface[MAXSTR]; FILE *routefd = NULL; if ((routefd = fopen(PROCROUTE, "r")) == NULL) { snprintf(errmsg, errmsglen , "Cannot open %s for reading" , PROCROUTE); rc = OCF_ERR_GENERIC; goto out; } /* Skip first (header) line */ if (fgets(buf, sizeof(buf), routefd) == NULL) { snprintf(errmsg, errmsglen , "Cannot skip first line from %s" , PROCROUTE); rc = OCF_ERR_GENERIC; goto out; } *best_netmask = 0; while (fgets(buf, sizeof(buf), routefd) != NULL) { if (sscanf(buf, "%[^\t]\t%lx%lx%lx%lx%lx%lx%lx" , interface, &dest, &gw, &flags, &refcnt, &use , &metric, &mask) != 8) { snprintf(errmsg, errmsglen, "Bad line in %s: %s" , PROCROUTE, buf); rc = OCF_ERR_GENERIC; goto out; } if ( (in->s_addr&mask) == (in_addr_t)(dest&mask) && metric <= best_metric && mask >= *best_netmask) { best_metric = metric; *best_netmask = mask; strncpy(best_if, interface, best_iflen); } } if (best_metric == LONG_MAX) { snprintf(errmsg, errmsglen, "No route to %s\n", address); rc = OCF_ERR_GENERIC; } out: if (routefd) { fclose(routefd); } return(rc); } static int SearchUsingRouteCmd (char *address, struct in_addr *in , struct in_addr *addr_out, char *best_if, size_t best_iflen , unsigned long *best_netmask , char *errmsg, int errmsglen) { char mask[20]; char routecmd[MAXSTR]; int best_metric = INT_MAX; char buf[2048]; char interface[MAXSTR]; char *cp, *sp; int done = 0; FILE *routefd = NULL; uint32_t maskbits; /* Open route and get the information */ snprintf (routecmd, sizeof(routecmd), "%s %s %s" , ROUTE, ROUTEPARM, address); routefd = popen (routecmd, "r"); if (routefd == NULL) return (OCF_ERR_GENERIC); mask[0] = EOS; interface[0] = EOS; while ((done < 3) && fgets(buf, sizeof(buf), routefd)) { int buflen = strnlen(buf, sizeof(buf)); /*cp = buf;*/ sp = buf + buflen; while (sp!=buf && isspace((int)*(sp-1))) { --sp; } *sp = EOS; if (strstr (buf, "mask:")) { /*strsep(&cp, ":");cp++;*/ strtok(buf, ":"); cp = strtok(NULL, ":"); if (cp) { cp++; strncpy(mask, cp, sizeof(mask) - 1); *(mask + sizeof(mask) - 1) = '\0'; done++; } } if (strstr (buf, "interface:")) { /*strsep(&cp, ":");cp++;*/ strtok(buf, ":"); cp = strtok(NULL, ":"); if (cp) { cp++; strncpy(interface, cp, sizeof(interface) - 1); *(interface + sizeof(interface) - 1) = '\0'; done++; } } } pclose(routefd); /* * Check to see if mask isn't available. It may not be * returned if multiple IP's are defined. * use 255.255.255.255 for mask then */ /* I'm pretty sure this is the wrong behavior... * I think the right behavior is to declare an error and give up. * The admin didn't define his routes correctly. Fix them. * It's useless to take over an IP address with no way to * return packets to the originator. Without the right subnet * mask, you can't reply to any packets you receive. */ if (strnlen(mask, sizeof(mask)) == 0) { strncpy (mask, "255.255.255.255", sizeof(mask)); } /* * Solaris (at least) can return the word "default" for mask and dest. * For the moment, let's interpret this as: * mask: 0.0.0.0 * This was manifesting itself under "BasicSanityCheck", which tries * to use a remote IP number; these typically use the "default" route. * Better schemes are warmly invited... */ #ifdef MASK_DEFAULT_TO_ZERO if (strncmp(mask, "default", sizeof("default")) == 0) { strncpy (mask, "0.0.0.0", sizeof(mask)); } #endif if (inet_pton(AF_INET, mask, &maskbits) <= 0) { snprintf(errmsg, errmsglen, "mask [%s] not valid.", mask); return(OCF_ERR_CONFIGURED); } if (inet_pton(AF_INET, address, addr_out) <= 0) { snprintf(errmsg, errmsglen , "IP address [%s] not valid.", address); return(OCF_ERR_CONFIGURED); } if ((in->s_addr & maskbits) == (addr_out->s_addr & maskbits)) { if (interface[0] == EOS) { snprintf(errmsg, errmsglen, "No interface found."); return(OCF_ERR_GENERIC); } best_metric = 0; *best_netmask = maskbits; strncpy(best_if, interface, best_iflen); } if (best_metric == INT_MAX) { snprintf(errmsg, errmsglen, "No route to %s\n", address); return(OCF_ERR_GENERIC); } return (OCF_SUCCESS); } /* * Getaddress gets all its real parameters from the OCF environment * variables that its callers already use. */ void GetAddress (char **address, char **netmaskbits , char **bcast_arg, char **if_specified) { /* * Here are out input environment variables: * * OCF_RESKEY_ip ip address * OCF_RESKEY_cidr_netmask netmask of interface * OCF_RESKEY_broadcast broadcast address for interface * OCF_RESKEY_nic interface to assign to * */ *address = getenv("OCF_RESKEY_ip"); *netmaskbits = getenv("OCF_RESKEY_cidr_netmask"); if (*netmaskbits == NULL || **netmaskbits == EOS) { *netmaskbits = getenv("OCF_RESKEY_netmask"); } *bcast_arg = getenv("OCF_RESKEY_broadcast"); *if_specified = getenv("OCF_RESKEY_nic"); } int ConvertNetmaskBitsToInt(char *netmaskbits) { size_t nmblen = strnlen(netmaskbits, 3); /* Maximum netmask is 32 */ if (nmblen > 2 || nmblen == 0 || (strspn(netmaskbits, "0123456789") != nmblen)) return -1; else return atoi(netmaskbits); } void ValidateNetmaskBits(int bits, unsigned long *netmask) { /* Maximum netmask is 32 */ if (bits < 1 || bits > 32) { fprintf(stderr , "Invalid netmask specification [%d]" , bits); usage(OCF_ERR_CONFIGURED); /*not reached */ } bits = 32 - bits; *netmask = (1L<<(bits))-1L; *netmask = ((~(*netmask))&0xffffffffUL); *netmask = htonl(*netmask); } int ValidateIFName(const char *ifname, struct ifreq *ifr) { int skfd = -1; char *colonptr; if ( (skfd = socket(PF_INET, SOCK_DGRAM, 0)) == -1 ) { fprintf(stderr, "%s\n", strerror(errno)); return -2; } strncpy(ifr->ifr_name, ifname, IFNAMSIZ - 1); *(ifr->ifr_name + sizeof(ifr->ifr_name) - 1) = '\0'; /* Contain a ":"? Probably an error, but treat as warning at present */ if ((colonptr = strchr(ifname, ':')) != NULL) { fprintf(stderr, "%s: warning: name may be invalid\n", ifr->ifr_name); } if (ioctl(skfd, SIOCGIFFLAGS, ifr) < 0) { fprintf(stderr, "%s: unknown interface: %s\n" , ifr->ifr_name, strerror(errno)); close(skfd); /* return -1 only if ifname is known to be invalid */ return -1; } close(skfd); return 0; } int netmask_bits(unsigned long netmask) { int j; netmask = netmask & 0xFFFFFFFFUL; for (j=0; j <= 32; ++j) { if ((netmask >> j)&0x1) { break; } } return 32 - j; } char * get_first_loopback_netdev(char * output) { char buf[512]; FILE * fd = NULL; char *rc = NULL; if (!output) { fprintf(stderr, "output buf is a null pointer.\n"); goto out; } fd = fopen(PATH_PROC_NET_DEV, "r"); if (!fd) { fprintf(stderr, "Warning: cannot open %s (%s).\n", PATH_PROC_NET_DEV, strerror(errno)); goto out; } /* Skip the first two lines */ if (!fgets(buf, sizeof(buf), fd) || !fgets(buf, sizeof(buf), fd)) { fprintf(stderr, "Warning: cannot read header from %s.\n", PATH_PROC_NET_DEV); goto out; } while (fgets(buf, sizeof(buf), fd)) { char name[IFNAMSIZ]; if (NULL == get_ifname(buf, name)) { /* Maybe somethin is wrong, anyway continue */ continue; } if (is_loopback_interface(name)) { strncpy(output, name, IFNAMSIZ); rc = output; goto out; } } out: if (fd) { fclose(fd); } return rc; } int is_loopback_interface(char * ifname) { struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); if (ValidateIFName(ifname, &ifr) < 0) return 0; if (ifr.ifr_flags & IFF_LOOPBACK) { /* this is a loopback device. */ return 1; } else { return 0; } } char * get_ifname(char * buf, char * ifname) { char * start, * end, * buf_border; buf_border = buf + strnlen(buf, 512); start = buf; while (isspace((int) *start) && (start != buf_border)) { start++; } end = start; while ((*end != ':') && (end != buf_border)) { end++; } if ( start == buf_border || end == buf_border ) { /* Over the border of buf */ return NULL; } *end = '\0'; strncpy(ifname, start, IFNAMSIZ); return ifname; } int ConvertQuadToInt(char *dest) { struct in_addr ad; if (inet_pton(AF_INET, dest, &ad) <= 0) return -1; return netmask_bits(ntohl(ad.s_addr)); } int main(int argc, char ** argv) { char * address = NULL; char * bcast_arg = NULL; char * netmaskbits = NULL; struct in_addr in; struct in_addr addr_out; unsigned long netmask = 0; char best_if[MAXSTR]; char * if_specified = NULL; struct ifreq ifr; unsigned long best_netmask = UINT_MAX; int argerrs = 0; int nmbits; cmdname=argv[0]; memset(&addr_out, 0, sizeof(addr_out)); memset(&in, 0, sizeof(in)); memset(&ifr, 0, sizeof(ifr)); switch (argc) { case 1: /* No -C argument */ break; case 2: /* Hopefully a -C argument */ if (strncmp(argv[1], "-C", sizeof("-C")) != 0) { argerrs=1; } OutputInCIDR=1; break; default: argerrs=1; break; } if (argerrs) { usage(OCF_ERR_ARGS); /* not reached */ return(1); } GetAddress (&address, &netmaskbits, &bcast_arg , &if_specified); if (address == NULL || *address == EOS) { fprintf(stderr, "ERROR: IP address parameter is mandatory."); usage(OCF_ERR_CONFIGURED); /* not reached */ } /* Is the IP address we're supposed to find valid? */ if (inet_pton(AF_INET, address, (void *)&in) <= 0) { fprintf(stderr, "IP address [%s] not valid.", address); usage(OCF_ERR_CONFIGURED); /* not reached */ } if (netmaskbits != NULL && *netmaskbits != EOS) { if (strchr(netmaskbits, '.') != NULL) { nmbits = ConvertQuadToInt(netmaskbits); fprintf(stderr, "Converted dotted-quad netmask to CIDR as: %d\n", nmbits); }else{ nmbits = ConvertNetmaskBitsToInt(netmaskbits); } if (nmbits < 0) { fprintf(stderr, "Invalid netmask specification" " [%s]", netmaskbits); usage(OCF_ERR_CONFIGURED); /*not reached */ } /* Validate the netmaskbits field */ ValidateNetmaskBits (nmbits, &netmask); } if (if_specified != NULL && *if_specified != EOS) { if(ValidateIFName(if_specified, &ifr) < 0) { usage(OCF_ERR_CONFIGURED); /* not reached */ } strncpy(best_if, if_specified, sizeof(best_if) - 1); *(best_if + sizeof(best_if) - 1) = '\0'; }else{ SearchRoute **sr = search_mechs; char errmsg[MAXSTR] = "No valid mechanisms"; int rc = OCF_ERR_GENERIC; strcpy(best_if, "UNKNOWN"); while (*sr) { errmsg[0] = '\0'; rc = (*sr) (address, &in, &addr_out, best_if , sizeof(best_if) , &best_netmask, errmsg, sizeof(errmsg)); if (!rc) { /* Mechanism worked */ break; } sr++; } if (rc != 0) { /* No route, or all mechanisms failed */ if (*errmsg) { fprintf(stderr, "%s", errmsg); } return(rc); } } - if (netmaskbits) { + if (netmaskbits != NULL && *netmaskbits != EOS) { best_netmask = netmask; }else if (best_netmask == 0L) { /* On some distributions, there is no loopback related route item, this leads to the error here. My fix may be not good enough, please FIXME */ if (0 == strncmp(address, "127", 3)) { if (NULL != get_first_loopback_netdev(best_if)) { best_netmask = 0x000000ff; } else { fprintf(stderr, "No loopback interface found.\n"); return(OCF_ERR_GENERIC); } } else { fprintf(stderr , "ERROR: Cannot use default route w/o netmask [%s]\n" , address); return(OCF_ERR_GENERIC); } } /* Did they tell us the broadcast address? */ if (bcast_arg && *bcast_arg != EOS) { /* Yes, they gave us a broadcast address. * It at least should be a valid IP address */ struct in_addr bcast_addr; if (inet_pton(AF_INET, bcast_arg, (void *)&bcast_addr) <= 0) { fprintf(stderr, "Invalid broadcast address [%s].", bcast_arg); usage(OCF_ERR_CONFIGURED); /* not reached */ } best_netmask = htonl(best_netmask); if (!OutputInCIDR) { printf("%s\tnetmask %d.%d.%d.%d\tbroadcast %s\n" , best_if , (int)((best_netmask>>24) & 0xff) , (int)((best_netmask>>16) & 0xff) , (int)((best_netmask>>8) & 0xff) , (int)(best_netmask & 0xff) , bcast_arg); }else{ printf("%s\tnetmask %d\tbroadcast %s\n" , best_if , netmask_bits(best_netmask) , bcast_arg); } }else{ /* No, we use a common broadcast address convention */ unsigned long def_bcast; /* Common broadcast address */ def_bcast = (in.s_addr | (~best_netmask)); #if DEBUG fprintf(stderr, "best_netmask = %08lx, def_bcast = %08lx\n" , best_netmask, def_bcast); #endif /* Make things a bit more machine-independent */ best_netmask = htonl(best_netmask); def_bcast = htonl(def_bcast); if (!OutputInCIDR) { printf("%s\tnetmask %d.%d.%d.%d\tbroadcast %d.%d.%d.%d\n" , best_if , (int)((best_netmask>>24) & 0xff) , (int)((best_netmask>>16) & 0xff) , (int)((best_netmask>>8) & 0xff) , (int)(best_netmask & 0xff) , (int)((def_bcast>>24) & 0xff) , (int)((def_bcast>>16) & 0xff) , (int)((def_bcast>>8) & 0xff) , (int)(def_bcast & 0xff)); }else{ printf("%s\tnetmask %d\tbroadcast %d.%d.%d.%d\n" , best_if , netmask_bits(best_netmask) , (int)((def_bcast>>24) & 0xff) , (int)((def_bcast>>16) & 0xff) , (int)((def_bcast>>8) & 0xff) , (int)(def_bcast & 0xff)); } } return(0); } void usage(int ec) { fprintf(stderr, "\n" "%s version 2.99.1 Copyright Alan Robertson\n" "\n" "Usage: %s [-C]\n" "Options:\n" " -C: Output netmask as the number of bits rather " "than as 4 octets.\n" "Environment variables:\n" "OCF_RESKEY_ip ip address (mandatory!)\n" "OCF_RESKEY_cidr_netmask netmask of interface\n" "OCF_RESKEY_broadcast broadcast address for interface\n" "OCF_RESKEY_nic interface to assign to\n" , cmdname, cmdname); exit(ec); } /* Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT eth0 33D60987 00000000 0005 0 0 0 FFFFFFFF 0 0 0 eth0 00D60987 00000000 0001 0 0 0 00FFFFFF 0 0 0 lo 0000007F 00000000 0001 0 0 0 000000FF 0 0 0 eth0 00000000 FED60987 0003 0 0 0 00000000 0 0 0 netstat -rn outpug from RedHat Linux 6.0 Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 192.168.85.2 0.0.0.0 255.255.255.255 UH 0 0 0 eth1 10.0.0.2 0.0.0.0 255.255.255.255 UH 0 0 0 eth2 208.132.134.61 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 208.132.134.32 0.0.0.0 255.255.255.224 U 0 0 0 eth0 192.168.85.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo 0.0.0.0 208.132.134.33 0.0.0.0 UG 0 0 0 eth0 |-------------------------------------------------------------------------------- netstat -rn output from FreeBSD 3.3 Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default 209.61.94.161 UGSc 3 8 pn0 192.168 link#1 UC 0 0 xl0 192.168.0.2 0:60:8:a4:91:fd UHLW 0 38 lo0 192.168.0.255 ff:ff:ff:ff:ff:ff UHLWb 1 7877 xl0 209.61.94.160/29 link#2 UC 0 0 pn0 209.61.94.161 0:a0:cc:26:c2:ea UHLW 6 17265 pn0 1105 209.61.94.162 0:a0:cc:27:1c:fb UHLW 1 568 pn0 1098 209.61.94.163 0:a0:cc:29:1f:86 UHLW 0 4749 pn0 1095 209.61.94.166 0:a0:cc:27:2d:e1 UHLW 0 12 lo0 209.61.94.167 ff:ff:ff:ff:ff:ff UHLWb 0 10578 pn0 |-------------------------------------------------------------------------------- netstat -rn output from FreeBSD 4.2 Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default 64.65.195.1 UGSc 1 11 dc0 64.65.195/24 link#1 UC 0 0 dc0 => 64.65.195.1 0:3:42:3b:0:dd UHLW 2 0 dc0 1131 64.65.195.184 0:a0:cc:29:1f:86 UHLW 2 18098 dc0 1119 64.65.195.194 0:a0:cc:27:2d:e1 UHLW 3 335161 dc0 943 64.65.195.200 52:54:0:db:33:b3 UHLW 0 13 dc0 406 64.65.195.255 ff:ff:ff:ff:ff:ff UHLWb 1 584 dc0 127.0.0.1 127.0.0.1 UH 0 0 lo0 192.168/16 link#2 UC 0 0 vx0 => 192.168.0.1 0:20:af:e2:f0:36 UHLW 0 2 lo0 192.168.255.255 ff:ff:ff:ff:ff:ff UHLWb 0 1 vx0 Internet6: Destination Gateway Flags Netif Expire ::1 ::1 UH lo0 fe80::%dc0/64 link#1 UC dc0 fe80::%vx0/64 link#2 UC vx0 fe80::%lo0/64 fe80::1%lo0 Uc lo0 ff01::/32 ::1 U lo0 ff02::%dc0/32 link#1 UC dc0 ff02::%vx0/32 link#2 UC vx0 ff02::%lo0/32 fe80::1%lo0 UC lo0 */