| /* Shared library add-on to iptables to add realm matching support. */ |
| #include <stdio.h> |
| #include <netdb.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <errno.h> |
| #include <ctype.h> |
| #include <getopt.h> |
| #if defined(__GLIBC__) && __GLIBC__ == 2 |
| #include <net/ethernet.h> |
| #else |
| #include <linux/if_ether.h> |
| #endif |
| #include <xtables.h> |
| #include <linux/netfilter_ipv4/ipt_realm.h> |
| |
| static void realm_help(void) |
| { |
| printf( |
| "realm match options:\n" |
| "[!] --realm value[/mask]\n" |
| " Match realm\n"); |
| } |
| |
| static const struct option realm_opts[] = { |
| { "realm", 1, NULL, '1' }, |
| { .name = NULL } |
| }; |
| |
| struct realmname { |
| int id; |
| char* name; |
| int len; |
| struct realmname* next; |
| }; |
| |
| /* array of realms from /etc/iproute2/rt_realms */ |
| static struct realmname *realms; |
| /* 1 if loading failed */ |
| static int rdberr; |
| |
| static void load_realms(void) |
| { |
| const char* rfnm = "/etc/iproute2/rt_realms"; |
| char buf[512]; |
| FILE *fil; |
| char *cur, *nxt; |
| int id; |
| struct realmname *oldnm = NULL, *newnm = NULL; |
| |
| fil = fopen(rfnm, "r"); |
| if (!fil) { |
| rdberr = 1; |
| return; |
| } |
| |
| while (fgets(buf, sizeof(buf), fil)) { |
| cur = buf; |
| while ((*cur == ' ') || (*cur == '\t')) |
| cur++; |
| if ((*cur == '#') || (*cur == '\n') || (*cur == 0)) |
| continue; |
| |
| /* iproute2 allows hex and dec format */ |
| errno = 0; |
| id = strtoul(cur, &nxt, strncmp(cur, "0x", 2) ? 10 : 16); |
| if ((nxt == cur) || errno) |
| continue; |
| |
| /* same boundaries as in iproute2 */ |
| if (id < 0 || id > 255) |
| continue; |
| cur = nxt; |
| |
| if (!isspace(*cur)) |
| continue; |
| while ((*cur == ' ') || (*cur == '\t')) |
| cur++; |
| if ((*cur == '#') || (*cur == '\n') || (*cur == 0)) |
| continue; |
| nxt = cur; |
| while ((*nxt != 0) && !isspace(*nxt)) |
| nxt++; |
| if (nxt == cur) |
| continue; |
| |
| /* found valid data */ |
| newnm = malloc(sizeof(struct realmname)); |
| if (newnm == NULL) { |
| perror("libipt_realm: malloc failed"); |
| exit(1); |
| } |
| newnm->id = id; |
| newnm->len = nxt - cur; |
| newnm->name = malloc(newnm->len + 1); |
| if (newnm->name == NULL) { |
| perror("libipt_realm: malloc failed"); |
| exit(1); |
| } |
| strncpy(newnm->name, cur, newnm->len); |
| newnm->name[newnm->len] = 0; |
| newnm->next = NULL; |
| |
| if (oldnm) |
| oldnm->next = newnm; |
| else |
| realms = newnm; |
| oldnm = newnm; |
| } |
| |
| fclose(fil); |
| } |
| |
| /* get realm id for name, -1 if error/not found */ |
| static int realm_name2id(const char* name) |
| { |
| struct realmname* cur; |
| |
| if ((realms == NULL) && (rdberr == 0)) |
| load_realms(); |
| cur = realms; |
| if (cur == NULL) |
| return -1; |
| while (cur) { |
| if (!strncmp(name, cur->name, cur->len + 1)) |
| return cur->id; |
| cur = cur->next; |
| } |
| return -1; |
| } |
| |
| /* get realm name for id, NULL if error/not found */ |
| static const char *realm_id2name(int id) |
| { |
| struct realmname* cur; |
| |
| if ((realms == NULL) && (rdberr == 0)) |
| load_realms(); |
| cur = realms; |
| if (cur == NULL) |
| return NULL; |
| while (cur) { |
| if (id == cur->id) |
| return cur->name; |
| cur = cur->next; |
| } |
| return NULL; |
| } |
| |
| static int realm_parse(int c, char **argv, int invert, unsigned int *flags, |
| const void *entry, struct xt_entry_match **match) |
| { |
| struct ipt_realm_info *realminfo = (struct ipt_realm_info *)(*match)->data; |
| int id; |
| |
| switch (c) { |
| char *end; |
| case '1': |
| xtables_check_inverse(optarg, &invert, &optind, 0, argv); |
| end = optarg = optarg; |
| realminfo->id = strtoul(optarg, &end, 0); |
| if (end != optarg && (*end == '/' || *end == '\0')) { |
| if (*end == '/') |
| realminfo->mask = strtoul(end+1, &end, 0); |
| else |
| realminfo->mask = 0xffffffff; |
| if (*end != '\0' || end == optarg) |
| xtables_error(PARAMETER_PROBLEM, |
| "Bad realm value `%s'", optarg); |
| } else { |
| id = realm_name2id(optarg); |
| if (id == -1) |
| xtables_error(PARAMETER_PROBLEM, |
| "Realm `%s' not found", optarg); |
| realminfo->id = id; |
| realminfo->mask = 0xffffffff; |
| } |
| if (invert) |
| realminfo->invert = 1; |
| *flags = 1; |
| break; |
| |
| default: |
| return 0; |
| } |
| return 1; |
| } |
| |
| static void |
| print_realm(unsigned long id, unsigned long mask, int numeric) |
| { |
| const char* name = NULL; |
| |
| if (mask != 0xffffffff) |
| printf("0x%lx/0x%lx ", id, mask); |
| else { |
| if (numeric == 0) |
| name = realm_id2name(id); |
| if (name) |
| printf("%s ", name); |
| else |
| printf("0x%lx ", id); |
| } |
| } |
| |
| static void realm_print(const void *ip, const struct xt_entry_match *match, |
| int numeric) |
| { |
| const struct ipt_realm_info *ri = (const void *)match->data; |
| |
| if (ri->invert) |
| printf("! "); |
| |
| printf("realm "); |
| print_realm(ri->id, ri->mask, numeric); |
| } |
| |
| static void realm_save(const void *ip, const struct xt_entry_match *match) |
| { |
| const struct ipt_realm_info *ri = (const void *)match->data; |
| |
| if (ri->invert) |
| printf("! "); |
| |
| printf("--realm "); |
| print_realm(ri->id, ri->mask, 0); |
| } |
| |
| static void realm_check(unsigned int flags) |
| { |
| if (!flags) |
| xtables_error(PARAMETER_PROBLEM, |
| "realm match: You must specify `--realm'"); |
| } |
| |
| static struct xtables_match realm_mt_reg = { |
| .name = "realm", |
| .version = XTABLES_VERSION, |
| .family = NFPROTO_IPV4, |
| .size = XT_ALIGN(sizeof(struct ipt_realm_info)), |
| .userspacesize = XT_ALIGN(sizeof(struct ipt_realm_info)), |
| .help = realm_help, |
| .parse = realm_parse, |
| .final_check = realm_check, |
| .print = realm_print, |
| .save = realm_save, |
| .extra_opts = realm_opts, |
| }; |
| |
| void _init(void) |
| { |
| xtables_register_match(&realm_mt_reg); |
| } |