Squid internals

ACL checks (acl.c)
Main functions
checklist = aclCheckList(acl_access, request, ident)
/* Create a match checklist against 'acl_access' */
aclNBCheck(checklist, callback, callback_data)
/* Begin an ACL check. Call callback when complete */
aclCheckListFree(checklist)
/* Finish with the checklist */
retval = aclCheckFast(acl_access, checklist)
/* check the given acl/checklist quickly (no blocking!) */
Used for simple acl checks that won't require blocking
Think checking idents against regexps, as an example
aclCheck(checklist)
/* Implement the checks the ACLs will need */
ip / dns lookups
proxy auth
ident requests?
aclMatchAclList(acl_list, checklist)
/* Match against the list of acls */
aclMatchAcl(acl, checklist)
/* Actually match against all of the normal acl types */