pj_hash_calc_tolower() might return a different hash value

[riza]

Example scenario:

1. Received INVITE with branch=z9hG4bK%999999f
2. Respond with 100
3. Respond with 180
4. Received CANCEL
5. Respond with "481 Call/Transaction Does Not Exist"

By default, sip_transaction.c enabled PRECALC_HASH which calculated the hash value using pj_hash_calc_lower().

char lower = (char)pj_tolower(key->ptr[i]);

When setting the hash, the value was calculated using

const pj_uint8_t *p = (const pj_uint8_t*)key,*end = p + keylen;
hash = hash * PJ_HASH_MULTIPLIER + pj_tolower(*p);

The branch/key contain %99, which will be stored as 0x99,
the calculated hash value will differ.

Thanks to Fredrik Hansson for the report.

[riza]

In r5600:

Fixed #2020: Method pj_hash_calc_tolower() might return a different hash
value.