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@wenjianhn
Created January 29, 2015 03:30
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Test if setsockopt(SO_PRIORITY) sets the IP type-of-service (TOS) field or not.
#include <assert.h>
#include <netinet/ip.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
void test_setsockopt()
{
int priority = 6;
int iptos = IPTOS_CLASS_CS6;
int fd = socket(AF_INET, SOCK_STREAM, 0);
if(setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &priority,
sizeof(priority)) < 0){
printf("Oh no\n");
}
int tos = -1;
int optlen = sizeof(tos);
if (getsockopt(fd, IPPROTO_IP, IP_TOS, &tos, &optlen) < 0){
printf("Oh no\n");
}
if (tos == 0){
printf("The man page lies or the kernel is buggy\n");
printf("setsockopt(SO_PRIORITY) didn't set the IP type-of-service (TOS) field.\n");
} else {
printf("the man page doesn't lie\n");
}
close(fd);
}
int main(void)
{
// background: https://ocrete.ca/2009/07/24/when-a-man-page-lies/
test_setsockopt();
return 0;
}
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