diff options
Diffstat (limited to 'src/shared')
| -rw-r--r-- | src/shared/dns-domain.c | 22 | ||||
| -rw-r--r-- | src/shared/dns-domain.h | 1 |
2 files changed, 23 insertions, 0 deletions
diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c index 33925bfbd1..8a0dec1540 100644 --- a/src/shared/dns-domain.c +++ b/src/shared/dns-domain.c @@ -529,6 +529,28 @@ int dns_name_endswith(const char *name, const char *suffix) { } } +int dns_name_between(const char *a, const char *b, const char *c) { + int n; + + /* Determine if b is strictly greater than a and strictly smaller than c. + We consider the order of names to be circular, so that if a is + strictly greater than c, we consider b to be between them if it is + either greater than a or smaller than c. This is how the canonical + DNS name order used in NSEC records work. */ + + n = dns_name_compare_func(a, c); + if (n == 0) + return -EINVAL; + else if (n < 0) + /* a<---b--->c */ + return dns_name_compare_func(a, b) < 0 && + dns_name_compare_func(b, c) < 0; + else + /* <--b--c a--b--> */ + return dns_name_compare_func(b, c) < 0 || + dns_name_compare_func(a, b) < 0; +} + int dns_name_reverse(int family, const union in_addr_union *a, char **ret) { const uint8_t *p; int r; diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h index 5728ce34bb..bd50ad3e6d 100644 --- a/src/shared/dns-domain.h +++ b/src/shared/dns-domain.h @@ -50,6 +50,7 @@ unsigned long dns_name_hash_func(const void *s, const uint8_t hash_key[HASH_KEY_ int dns_name_compare_func(const void *a, const void *b); extern const struct hash_ops dns_name_hash_ops; +int dns_name_between(const char *a, const char *b, const char *c); int dns_name_equal(const char *x, const char *y); int dns_name_endswith(const char *name, const char *suffix); |