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path: root/src/network/lookup.h
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2018-10-04allow freeaddrinfo of arbitrary sublists of addrinfo listRich Felker1-0/+12
the specification for freeaddrinfo allows it to be used to free "arbitrary sublists" of the list returned by getaddrinfo. it's not clearly stated how such sublists come into existence, but the interpretation seems to be that the application can edit the ai_next pointers to cut off a portion of the list and then free it. actual freeing of individual list slots is contrary to the design of our getaddrinfo implementation, which has no failure paths after making a single allocation, so that light callers can avoid linking realloc/free. freeing individual slots is also incompatible with sharing the string for ai_canonname, which the current implementation does despite no requirement that it be present except on the first result. so, rather than actually freeing individual slots, provide a way to find the start of the allocated array, and reference-count it, freeing the memory all at once after the last slot has been freed. since the language in the spec is "arbitrary sublists", no provision for handling other constructs like multiple lists glued together, circular links, etc. is made. presumably passing such a construct to freeaddrinfo produces undefined behavior.
2018-09-12apply hidden visibility to various remaining internal interfacesRich Felker1-6/+7
2018-09-12move __res_msend_rc declaration to lookup.hRich Felker1-0/+1
unlike the other res/dn functions, this one is tied to struct resolvconf which is not a public interface, so put it in the private header for its subsystem.
2018-09-12move and deduplicate declarations of __dns_parse to make it checkableRich Felker1-0/+2
the source file for this function is completely standalone, but it doesn't seem worth adding a header just for it, so declare it in lookup.h for now.
2016-01-28factor resolv.conf parsing out of res_msend to its own fileRich Felker1-0/+11
this change is made in preparation for adding search domains, for which higher-level code will need to parse resolv.conf. simply parsing it twice for each lookup would be one reasonable option, but the existing parser code was buggy anyway, which suggested to me that it's a bad idea to have two variants of this code in two different places. the old code in res_msend potentially misinterpreted overly long lines in resolv.conf, and stopped parsing after it found 3 nameservers, even if there were relevant options left to be parsed later in the file.
2015-02-07make getaddrinfo support SOCK_RAW and other socket typesRich Felker1-2/+2
all socket types are accepted at this point, but that may be changed at a later time if the behavior is not meaningful for other types. as before, omitting type (a value of 0) gives both UDP and TCP results, and SOCK_DGRAM or SOCK_STREAM restricts to UDP or TCP, respectively. for other socket types, the service name argument is required to be a null pointer, and the protocol number provided by the caller is used.
2014-06-21implement result address sorting in the resolver (getaddrinfo, etc.)Rich Felker1-0/+1
2014-06-04add support for reverse name lookups from hosts file to getnameinfoRich Felker1-0/+1
this also affects the legacy gethostbyaddr family, which uses getnameinfo as its backend. some other minor changes associated with the refactoring of source files are also made; in particular, the resolv.conf parser now uses the same code that's used elsewhere to handle ip literals, so as a side effect it can now accept a scope id for nameserver addressed with link-local scope.
2014-05-31refactor getaddrinfo and add support for most remaining featuresRich Felker1-0/+26
this is the first phase of the "resolver overhaul" project. conceptually, the results of getaddrinfo are a direct product of a list of address results and a list of service results. the new code makes this explicit by computing these lists separately and combining the results. this adds support for services that have both tcp and udp versions, where the caller has not specified which it wants, and eliminates a number of duplicate code paths which were all producing the final output addrinfo structures, but in subtly different ways, making it difficult to implement any of the features which were missing. in addition to the above benefits, the refactoring allows for legacy functions like gethostbyname to be implemented without using the getaddrinfo function itself. such changes to the legacy functions have not yet been made, however. further improvements include matching of service alias names from /etc/services (previously only the primary name was supported), returning multiple results from /etc/hosts (previously only the first matching line was honored), and support for the AI_V4MAPPED and AI_ALL flags. features which remain unimplemented are IDN translations (encoding non-ASCII hostnames for DNS lookup) and the AI_ADDRCONFIG flag. at this point, the DNS-based name resolving code is still based on the old interfaces in __dns.c, albeit somewhat simpler in its use of them. there may be some dead code which could already be removed, but changes to this layer will be a later phase of the resolver overhaul.