updated test: /*BINFMTC: -Wall -Wextra -Wno-unused-parameter test for getaddrinfo bug: getaddrinfo returns EAI_NONAME when it should return EAI_EAGAIN
getaddrinfo returns EAI_NONAME when it should return EAI_EAGAIN for hosts with A but no AAAA record and there is packet loss and/or a an overloaded dns server to easily reproduce, fake packet loss/overloaded dns server on linux do something like: # iptables -I OUTPUT -p udp -m udp --dport 53 -j DROP # iptables -I OUTPUT -p udp -m udp --dport 53 -j LOG --log-prefix "DROP DNS REQUEST " # iptables -I OUTPUT -p udp -m udp --dport 53 -m limit --limit 10/sec -j ACCEPT first */ #include <sys/types.h> #include <sys/socket.h> #include <netdb.h> #include <stdio.h> #include <stdlib.h> /* test host must have a A record but no AAAA record also note the final dot - otherwise a search entry in resolv.conf might cause the first test to fail, too */ const char* host="karme.de."; struct addrinfo hints; // all 0 int main(int argc, char** argv) { struct addrinfo* res; int i; hints.ai_family = AF_INET; /* first test should work on mosts setups (there is another bug involving mdns if it fails try to replace the hosts line in /etc/nsswitch.conf with something like: "hosts: files dns" ) */ for(i=0;i<1000;++i) { int r=getaddrinfo(host,0,&hints,&res); if(!((r==0)||(r==EAI_AGAIN))) { printf("%s:%d: error: r=%d %s\n",__FILE__,__LINE__,r,gai_strerror(r)); exit(EXIT_FAILURE); } if (!r) freeaddrinfo(res); } /* second test will fail sometimes what happens? DNS request for A record is sent but no answer is received DNS request for AAAA record is sent and answer without entries received now getaddrinfo returns EAI_NONAME when in fact it should return EAI_AGAIN */ hints.ai_family = AF_UNSPEC; for(i=0;i<1000;++i) { int r=getaddrinfo(host,0,&hints,&res); if(!((r==0)||(r==EAI_AGAIN))) { printf("%s:%d: error: r=%d %s\n",__FILE__,__LINE__,r,gai_strerror(r)); exit(EXIT_FAILURE); } if (!r) freeaddrinfo(res); } return EXIT_SUCCESS; } -- To UNSUBSCRIBE, email to debian-glibc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/87sj8t1llo....@karme.de