diff options
Diffstat (limited to 'src/shared/dns-domain.c')
| -rw-r--r-- | src/shared/dns-domain.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c index 423ccca9cc..e08143c3be 100644 --- a/src/shared/dns-domain.c +++ b/src/shared/dns-domain.c @@ -29,6 +29,7 @@ #include "hexdecoct.h" #include "parse-util.h" #include "string-util.h" +#include "utf8.h" int dns_label_unescape(const char **name, char *dest, size_t sz) { const char *n; @@ -749,3 +750,228 @@ int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len) { return out - buffer; } + +static bool srv_type_label_is_valid(const char *label, size_t n) { + size_t k; + + assert(label); + + if (n < 2) /* Label needs to be at least 2 chars long */ + return false; + + if (label[0] != '_') /* First label char needs to be underscore */ + return false; + + /* Second char must be a letter */ + if (!(label[1] >= 'A' && label[1] <= 'Z') && + !(label[1] >= 'a' && label[1] <= 'z')) + return false; + + /* Third and further chars must be alphanumeric or a hyphen */ + for (k = 2; k < n; k++) { + if (!(label[k] >= 'A' && label[k] <= 'Z') && + !(label[k] >= 'a' && label[k] <= 'z') && + !(label[k] >= '0' && label[k] <= '9') && + label[k] != '-') + return false; + } + + return true; +} + +int dns_srv_type_verify(const char *name) { + unsigned c = 0; + int r; + + if (!name) + return 0; + + for (;;) { + char label[DNS_LABEL_MAX]; + + /* This more or less implements RFC 6335, Section 5.1 */ + + r = dns_label_unescape(&name, label, sizeof(label)); + if (r == -EINVAL) + return 0; + if (r < 0) + return r; + if (r == 0) + break; + + if (c >= 2) + return 0; + + if (!srv_type_label_is_valid(label, r)) + return 0; + + c++; + } + + return c == 2; /* exactly two labels */ +} + +bool dns_service_name_is_valid(const char *name) { + size_t l; + + /* This more or less implements RFC 6763, Section 4.1.1 */ + + if (!name) + return false; + + if (!utf8_is_valid(name)) + return false; + + if (string_has_cc(name, NULL)) + return false; + + l = strlen(name); + if (l <= 0) + return false; + if (l > 63) + return false; + + return true; +} + +int dns_service_join(const char *name, const char *type, const char *domain, char **ret) { + _cleanup_free_ char *escaped = NULL, *n = NULL; + int r; + + assert(type); + assert(domain); + assert(ret); + + if (!dns_srv_type_verify(type)) + return -EINVAL; + + if (!name) + return dns_name_concat(type, domain, ret); + + if (!dns_service_name_is_valid(name)) + return -EINVAL; + + r = dns_label_escape(name, strlen(name), &escaped); + if (r < 0) + return r; + + r = dns_name_concat(type, domain, &n); + if (r < 0) + return r; + + return dns_name_concat(escaped, n, ret); +} + +static bool dns_service_name_label_is_valid(const char *label, size_t n) { + char *s; + + assert(label); + + if (memchr(label, 0, n)) + return false; + + s = strndupa(label, n); + return dns_service_name_is_valid(s); +} + +int dns_service_split(const char *joined, char **_name, char **_type, char **_domain) { + _cleanup_free_ char *name = NULL, *type = NULL, *domain = NULL; + const char *p = joined, *q = NULL, *d = NULL; + char a[DNS_LABEL_MAX], b[DNS_LABEL_MAX], c[DNS_LABEL_MAX]; + int an, bn, cn, r; + unsigned x = 0; + + assert(joined); + + /* Get first label from the full name */ + an = dns_label_unescape(&p, a, sizeof(a)); + if (an < 0) + return an; + + if (an > 0) { + x++; + + /* If there was a first label, try to get the second one */ + bn = dns_label_unescape(&p, b, sizeof(b)); + if (bn < 0) + return bn; + + if (bn > 0) { + x++; + + /* If there was a second label, try to get the third one */ + q = p; + cn = dns_label_unescape(&p, c, sizeof(c)); + if (cn < 0) + return cn; + + if (cn > 0) + x++; + } else + cn = 0; + } else + an = 0; + + if (x >= 2 && srv_type_label_is_valid(b, bn)) { + + if (x >= 3 && srv_type_label_is_valid(c, cn)) { + + if (dns_service_name_label_is_valid(a, an)) { + + /* OK, got <name> . <type> . <type2> . <domain> */ + + name = strndup(a, an); + if (!name) + return -ENOMEM; + + type = new(char, bn+1+cn+1); + if (!type) + return -ENOMEM; + strcpy(stpcpy(stpcpy(type, b), "."), c); + + d = p; + goto finish; + } + + } else if (srv_type_label_is_valid(a, an)) { + + /* OK, got <type> . <type2> . <domain> */ + + name = NULL; + + type = new(char, an+1+bn+1); + if (!type) + return -ENOMEM; + strcpy(stpcpy(stpcpy(type, a), "."), b); + + d = q; + goto finish; + } + } + + name = NULL; + type = NULL; + d = joined; + +finish: + r = dns_name_normalize(d, &domain); + if (r < 0) + return r; + + if (_domain) { + *_domain = domain; + domain = NULL; + } + + if (_type) { + *_type = type; + type = NULL; + } + + if (_name) { + *_name = name; + name = NULL; + } + + return 0; +} |