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A few minor tweaks to make code less braindead. Fixed-length piece of pool name now only used to hash when determinism is not required; otherwise,

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whole pool name is used.  Note that collisions between pool name hashes will lead to sensitivity to initialization order within the UID generator.
This commit is contained in:
Gilbert Clark gc355804@ohio.edu 2011-08-09 09:44:31 -07:00
parent df142b9c4b
commit e21feb8487
1 changed files with 2 additions and 8 deletions
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10
src/util.cc
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@ -1229,13 +1229,13 @@ uint64 calculate_unique_id(const std::string& pool)
if ( pool_iter == uid_pool.end() ) if ( pool_iter == uid_pool.end() )
{ {
// This is the first time we need a UID for this pool. // This is the first time we need a UID for this pool.
const size_t pool_sz = (pool.length() < 32) ? pool.length() : 32; //Only keep the first 32 characters of the pool name
if ( ! have_random_seed() ) if ( ! have_random_seed() )
{ {
// If we don't need deterministic output (as // If we don't need deterministic output (as
// indicated by a set seed), we calculate the // indicated by a set seed), we calculate the
// instance ID by hashing something likely to be // instance ID by hashing something likely to be
// globally unique. // globally unique.
const size_t pool_sz = (pool.length() < 32) ? pool.length() : 32; //Only keep the first 32 characters of the pool name
struct { struct {
char hostname[96]; char hostname[96];
char pool[32]; char pool[32];
@ -1258,7 +1258,7 @@ uint64 calculate_unique_id(const std::string& pool)
else else
{ {
// Generate determistic UIDs for each individual pool // Generate determistic UIDs for each individual pool
uid_instance = HashKey::HashBytes(pool.c_str(), strnlen(pool.c_str(), pool_sz)); uid_instance = HashKey::HashBytes(pool.c_str(), pool.length());
} }
// Guarantee no collisions (keep hashing until we get a unique instance) // Guarantee no collisions (keep hashing until we get a unique instance)
bool found_collision = true; bool found_collision = true;
@ -1276,16 +1276,10 @@ uint64 calculate_unique_id(const std::string& pool)
} }
// Our instance is unique. Huzzah. // Our instance is unique. Huzzah.
uid_pool.insert(std::make_pair(pool, BroUidEntry(uid_instance))); uid_pool.insert(std::make_pair(pool, BroUidEntry(uid_instance)));
pool_iter = uid_pool.end();
}
if(pool_iter == uid_pool.end())
{
pool_iter = uid_pool.find(pool); pool_iter = uid_pool.find(pool);
} }
assert(pool_iter != uid_pool.end()); // After all that work, wouldn't it be a shame...? assert(pool_iter != uid_pool.end()); // After all that work, wouldn't it be a shame...?
++(pool_iter->second.counter); ++(pool_iter->second.counter);
uint64_t h = HashKey::HashBytes(&(pool_iter->second), sizeof(pool_iter->second)); uint64_t h = HashKey::HashBytes(&(pool_iter->second), sizeof(pool_iter->second));
return h; return h;
} }