This fixes an upstream bug:

https://github.com/traviscross/mtr/issues/35

The patch is from

https://bugs.launchpad.net/mtr/+bug/1273486/comments/5

--- mtr-0.86/net.c 2014-12-09 03:20:57.000000000 -0800

+++ mtr-0.86/net.c 2015-03-20 09:43:55.576572132 -0700

@@ -301,7 +301,7 @@ void net_send_tcp(int index)

void net_send_tcp(int index)

{

int ttl, s;

- int opt = 1;

+ int flags;

int port;

struct sockaddr_storage local;

struct sockaddr_storage remote;

@@ -354,10 +354,10 @@ void net_send_tcp(int index)

exit(EXIT_FAILURE);

}

- opt = 1;

- if (ioctl(s, FIONBIO, &opt)) {

+ flags = fcntl(s, F_GETFL, 0);

+ if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1) {

display_clear();

- perror("ioctl FIONBIO");

+ perror("fcntl F_SETFL(O_NONBLOCK)");

exit(EXIT_FAILURE);

}