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Speed up ethernet entry (manuf and wka) parsing. 

This saves around 3% time (profiling a small capture file) at startup.
parse_ether_address_fast() was returning FALSE in some cases
where it shouldn't have, i.e.
- the test for the having hex chars incorrectly discarded any case where the
  msb of any address octet is set, i.e. any value from 80 to f0.
- it now allows ':' and '-' as a separator (so that many of the wka entries
  also match).
This commit is contained in:
Martin Mathieson 2020-10-24 20:38:00 +01:00 committed by Peter Wu
parent 63d045e7eb
commit 24d7ff72bb
1 changed files with 23 additions and 17 deletions
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40
epan/addr_resolv.c
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@ -1205,7 +1205,8 @@ host_lookup6(const ws_in6_addr *addr)
*/
/*
* Converts Ethernet addresses of the form aa:bb:cc or aa:bb:cc:dd:ee:ff/28. The
* Converts Ethernet addresses of the form aa:bb:cc or aa:bb:cc:dd:ee:ff/28.
* '-' is also supported as a separator. The
* octets must be exactly two hexadecimal characters and the mask must be either
* 28 or 36. Pre-condition: cp MUST be at least 21 bytes.
*/
@ -1235,43 +1236,48 @@ parse_ether_address_fast(const guchar *cp, ether_t *eth, unsigned int *mask,
};
const guint8 *str_to_nibble_usg = (const guint8 *)str_to_nibble;
if (cp[2] != ':' || cp[5] != ':') {
guchar sep = cp[2];
if ((sep != ':' && sep != '-') || cp[5] != sep) {
/* Unexpected separators. */
return FALSE;
}
guint8 num0 = (str_to_nibble_usg[cp[0]] << 4) | str_to_nibble_usg[cp[1]];
guint8 num1 = (str_to_nibble_usg[cp[3]] << 4) | str_to_nibble_usg[cp[4]];
guint8 num2 = (str_to_nibble_usg[cp[6]] << 4) | str_to_nibble_usg[cp[7]];
if (((num0 | num1 | num2) & 0x80)) {
/* N.B. store octet values in an int to detect invalid (-1) entries */
int num0 = (str_to_nibble_usg[cp[0]] << 4) | (gint8)str_to_nibble_usg[cp[1]];
int num1 = (str_to_nibble_usg[cp[3]] << 4) | (gint8)str_to_nibble_usg[cp[4]];
int num2 = (str_to_nibble_usg[cp[6]] << 4) | (gint8)str_to_nibble_usg[cp[7]];
if ((num0 | num1 | num2) & 0x100) {
/* Not hexadecimal numbers. */
return FALSE;
}
eth->addr[0] = num0;
eth->addr[1] = num1;
eth->addr[2] = num2;
eth->addr[0] = (guint8)num0;
eth->addr[1] = (guint8)num1;
eth->addr[2] = (guint8)num2;
if (cp[8] == '\0' && accept_mask) {
/* Indicate that this is a manufacturer ID (0 is not allowed as a mask). */
*mask = 0;
return TRUE;
} else if (cp[8] != ':' || !accept_mask) {
} else if (cp[8] != sep || !accept_mask) {
/* Format not handled by this fast path. */
return FALSE;
}
guint8 num3 = (str_to_nibble_usg[cp[9]] << 4) | str_to_nibble_usg[cp[10]];
guint8 num4 = (str_to_nibble_usg[cp[12]] << 4) | str_to_nibble_usg[cp[13]];
guint8 num5 = (str_to_nibble_usg[cp[15]] << 4) | str_to_nibble_usg[cp[16]];
if (((num3 | num4 | num5) & 0x80) || cp[11] != ':' || cp[14] != ':') {
/* N.B. store octet values in an int to detect invalid (-1) entries */
int num3 = (str_to_nibble_usg[cp[9]] << 4) | (gint8)str_to_nibble_usg[cp[10]];
int num4 = (str_to_nibble_usg[cp[12]] << 4) | (gint8)str_to_nibble_usg[cp[13]];
int num5 = (str_to_nibble_usg[cp[15]] << 4) | (gint8)str_to_nibble_usg[cp[16]];
if (((num3 | num4 | num5) & 0x100) || cp[11] != sep || cp[14] != sep) {
/* Not hexadecimal numbers or invalid separators. */
return FALSE;
}
eth->addr[3] = num3;
eth->addr[4] = num4;
eth->addr[5] = num5;
eth->addr[3] = (guint8)num3;
eth->addr[4] = (guint8)num4;
eth->addr[5] = (guint8)num5;
if (cp[17] == '\0') {
/* We got 6 bytes, so this is a MAC address (48 is not allowed as a mask). */
*mask = 48;