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authorDaniel Kahn Gillmor <dkg@fifthhorseman.net>2016-05-17 11:00:29 -0400
committerDaniel Kahn Gillmor <dkg@fifthhorseman.net>2016-05-17 16:55:20 -0400
commitdd4d201ab1c9456e1bffc39f9dec00a4a4619084 (patch)
treeca157d8ed22b9197380640af08b0785fdfacdcdf
parent1a7906ae914fd233305fff0acf4b9138ff944209 (diff)
util-lib: add ether_addr_from_string()
This isn't quite symmetrical to in_addr_from_string() because it also returns an offset indicating how much of the string was consumed by the matched pattern. This offset reporting is needed for either of the following use cases: * verifying the lack of trailing garbage after such an address * parsing subsequent data from the same string
-rw-r--r--src/basic/ether-addr-util.c69
-rw-r--r--src/basic/ether-addr-util.h2
2 files changed, 71 insertions, 0 deletions
diff --git a/src/basic/ether-addr-util.c b/src/basic/ether-addr-util.c
index a4d8d656da..5697e8d132 100644
--- a/src/basic/ether-addr-util.c
+++ b/src/basic/ether-addr-util.c
@@ -23,6 +23,7 @@
#include "ether-addr-util.h"
#include "macro.h"
+#include "string-util.h"
char* ether_addr_to_string(const struct ether_addr *addr, char buffer[ETHER_ADDR_TO_STRING_MAX]) {
assert(addr);
@@ -54,3 +55,71 @@ bool ether_addr_equal(const struct ether_addr *a, const struct ether_addr *b) {
a->ether_addr_octet[4] == b->ether_addr_octet[4] &&
a->ether_addr_octet[5] == b->ether_addr_octet[5];
}
+
+int ether_addr_from_string(const char *s, struct ether_addr *ret, size_t *offset) {
+ size_t pos = 0, n, field;
+ char sep = '\0';
+ const char *hex = HEXDIGITS, *hexoff;
+ size_t x;
+ bool touched;
+
+#define parse_fields(v) \
+ for (field = 0; field < ELEMENTSOF(v); field++) { \
+ touched = false; \
+ for (n = 0; n < (2 * sizeof(v[0])); n++) { \
+ if (s[pos] == '\0') \
+ break; \
+ hexoff = strchr(hex, s[pos]); \
+ if (hexoff == NULL) \
+ break; \
+ assert(hexoff >= hex); \
+ x = hexoff - hex; \
+ if (x >= 16) \
+ x -= 6; /* A-F */ \
+ assert(x < 16); \
+ touched = true; \
+ v[field] <<= 4; \
+ v[field] += x; \
+ pos++; \
+ } \
+ if (!touched) \
+ return -EINVAL; \
+ if (field < (ELEMENTSOF(v)-1)) { \
+ if (s[pos] != sep) \
+ return -EINVAL; \
+ else \
+ pos++; \
+ } \
+ }
+
+ assert(s);
+ assert(ret);
+
+ sep = s[strspn(s, hex)];
+ if (sep == '\n')
+ return -EINVAL;
+ if (strchr(":.-", sep) == NULL)
+ return -EINVAL;
+
+ if (sep == '.') {
+ uint16_t shorts[3] = { 0 };
+
+ parse_fields(shorts);
+
+ for (n = 0; n < ELEMENTSOF(shorts); n++) {
+ ret->ether_addr_octet[2*n] = ((shorts[n] & (uint16_t)0xff00) >> 8);
+ ret->ether_addr_octet[2*n + 1] = (shorts[n] & (uint16_t)0x00ff);
+ }
+ } else {
+ struct ether_addr out = { .ether_addr_octet = { 0 } };
+
+ parse_fields(out.ether_addr_octet);
+
+ for (n = 0; n < ELEMENTSOF(out.ether_addr_octet); n++)
+ ret->ether_addr_octet[n] = out.ether_addr_octet[n];
+ }
+
+ if (offset)
+ *offset = pos;
+ return 0;
+}
diff --git a/src/basic/ether-addr-util.h b/src/basic/ether-addr-util.h
index 074363793e..74e125a95f 100644
--- a/src/basic/ether-addr-util.h
+++ b/src/basic/ether-addr-util.h
@@ -35,3 +35,5 @@ bool ether_addr_equal(const struct ether_addr *a, const struct ether_addr *b);
static inline bool ether_addr_is_null(const struct ether_addr *addr) {
return ether_addr_equal(addr, &ETHER_ADDR_NULL);
}
+
+int ether_addr_from_string(const char *s, struct ether_addr *ret, size_t *offset);