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author | Yu Watanabe <watanabe.yu+github@gmail.com> | 2021-11-04 19:18:32 +0900 |
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committer | Yu Watanabe <watanabe.yu+github@gmail.com> | 2021-11-09 21:39:05 +0900 |
commit | 76a5d3dee27124e017a5ebbb1fe461b13d9415c2 (patch) | |
tree | 9e23232794c2288fc832b8d0bacfe6b9beeabb4e /src/basic/ether-addr-util.c | |
parent | 777c17b9d1a035c0a0a9efb747409514204ccbd7 (diff) | |
download | systemd-76a5d3dee27124e017a5ebbb1fe461b13d9415c2.tar.gz |
ether-addr-util: introduce parse_hw_addr()
Diffstat (limited to 'src/basic/ether-addr-util.c')
-rw-r--r-- | src/basic/ether-addr-util.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/src/basic/ether-addr-util.c b/src/basic/ether-addr-util.c index dc5b5b833d..0cc18b3115 100644 --- a/src/basic/ether-addr-util.c +++ b/src/basic/ether-addr-util.c @@ -165,3 +165,147 @@ int ether_addr_from_string(const char *s, struct ether_addr *ret) { return 0; } + +static int parse_hw_addr_one_field(const char **s, char sep, size_t len, uint8_t *buf) { + const char *hex = HEXDIGITS, *p; + uint16_t data = 0; + bool cont; + + assert(s); + assert(*s); + assert(IN_SET(len, 1, 2)); + assert(buf); + + p = *s; + + for (size_t i = 0; i < len * 2; i++) { + const char *hexoff; + size_t x; + + if (*p == '\0' || *p == sep) { + if (i == 0) + return -EINVAL; + break; + } + + hexoff = strchr(hex, *p); + if (!hexoff) + return -EINVAL; + + assert(hexoff >= hex); + x = hexoff - hex; + if (x >= 16) + x -= 6; /* A-F */ + + assert(x < 16); + data <<= 4; + data += x; + + p++; + } + + if (*p != '\0' && *p != sep) + return -EINVAL; + + switch (len) { + case 1: + buf[0] = data; + break; + case 2: + buf[0] = (data & 0xff00) >> 8; + buf[1] = data & 0xff; + break; + default: + assert_not_reached(); + } + + cont = *p == sep; + *s = p + cont; + return cont; +} + +int parse_hw_addr_full(const char *s, size_t expected_len, struct hw_addr_data *ret) { + size_t field_size, max_len, len = 0; + uint8_t bytes[HW_ADDR_MAX_SIZE]; + char sep; + int r; + + assert(s); + assert(expected_len <= HW_ADDR_MAX_SIZE || expected_len == SIZE_MAX); + assert(ret); + + /* This accepts the following formats: + * + * Dot separated 2 bytes format: xxyy.zzaa.bbcc + * Colon separated 1 bytes format: xx:yy:zz:aa:bb:cc + * Hyphen separated 1 bytes format: xx-yy-zz-aa-bb-cc + * + * Moreover, if expected_len == 0, 4, or 16, this also accepts: + * + * IPv4 format: used by IPv4 tunnel, e.g. ipgre + * IPv6 format: used by IPv6 tunnel, e.g. ip6gre + * + * The expected_len argument controls the length of acceptable addresses: + * + * 0: accepts 4 (AF_INET), 16 (AF_INET6), 6 (ETH_ALEN), or 20 (INFINIBAND_ALEN). + * SIZE_MAX: accepts arbitrary length, but at least one separator must be included. + * Otherwise: accepts addresses with matching length. + */ + + if (IN_SET(expected_len, 0, sizeof(struct in_addr), sizeof(struct in6_addr))) { + union in_addr_union a; + int family; + + if (expected_len == 0) + r = in_addr_from_string_auto(s, &family, &a); + else { + family = expected_len == sizeof(struct in_addr) ? AF_INET : AF_INET6; + r = in_addr_from_string(family, s, &a); + } + if (r >= 0) { + ret->length = FAMILY_ADDRESS_SIZE(family); + memcpy(ret->bytes, a.bytes, ret->length); + return 0; + } + } + + max_len = + expected_len == 0 ? INFINIBAND_ALEN : + expected_len == SIZE_MAX ? HW_ADDR_MAX_SIZE : expected_len; + sep = s[strspn(s, HEXDIGITS)]; + + if (sep == '.') + field_size = 2; + else if (IN_SET(sep, ':', '-')) + field_size = 1; + else + return -EINVAL; + + if (max_len % field_size != 0) + return -EINVAL; + + for (size_t i = 0; i < max_len / field_size; i++) { + r = parse_hw_addr_one_field(&s, sep, field_size, bytes + i * field_size); + if (r < 0) + return r; + if (r == 0) { + len = (i + 1) * field_size; + break; + } + } + + if (len == 0) + return -EINVAL; + + if (expected_len == 0) { + if (!IN_SET(len, 4, 16, ETH_ALEN, INFINIBAND_ALEN)) + return -EINVAL; + } else if (expected_len != SIZE_MAX) { + if (len != expected_len) + return -EINVAL; + } + + ret->length = len; + memcpy(ret->bytes, bytes, ret->length); + return 0; +} |