Re: [libvirt] [PATCHv2 13/13] Run radvd for virtual networks with IPv6 addresses

Running an instance of the router advertisement daemon (radvd) allows guests using the virtual network to automatically acquire an IPv6 address and default route. Note that acquiring an address only works for networks with a prefix length of exactly 64 - radvd is still run in other circumstances, and still advertises routes, but autoconf will not work because it requires exactly 64 bits of address info from the network prefix. This patch avoids a race condition with the pidfile by manually daemonizing radvd rather than allowing it to daemonize itself, then creating our own pidfile (in addition to radvd's own file, which is unnecessary). This is accomplished by exec'ing it with "--debug 1" in the commandline, and using virCommand's features to fork, create a pidfile, and detach from the newly forked process.

+ cmd = virCommandNewArgList(RADVD, "--debug", "1", + "--config", configfile, + "--pidfile", NULL); + virCommandAddArgFormat(cmd, "%s-bin", pidfile); + + virCommandSetPidFile(cmd, pidfile); + virCommandDaemonize(cmd); + + if (virCommandRun(cmd, NULL) < 0) + goto cleanup; + + if (virFileReadPid(NETWORK_PID_DIR, radvdpidbase, + &network->radvdPid) < 0) + goto cleanup; + + ret = 0; +cleanup: + virCommandFree(cmd); + VIR_FREE(configfile); + VIR_FREE(configstr); + virBufferFreeAndReset(&configbuf); + VIR_FREE(radvdpidbase); + VIR_FREE(pidfile);

static int -networkEnableIpForwarding(void) +networkEnableIpForwarding(int enableIPv4, int enableIPv6)