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#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <arpa/inet.h>
void _init(void);
int (*sys_connect)(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
int dscp_val = 0;
void _init(void) {
const char* err;
char* env_dscp;
env_dscp = getenv("DSCP");
if (env_dscp)
dscp_val = atoi(env_dscp) << 2;
sys_connect = dlsym(RTLD_NEXT, "connect");
err = dlerror();
if (err != NULL)
(void)fprintf(stderr, "libdscp:dlsym (connect): %s\n", err);
}
int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
int oerrno = errno;
setsockopt(sockfd, IPPROTO_IP, IP_TOS, &dscp_val, sizeof dscp_val);
setsockopt(sockfd, IPPROTO_IPV6, IPV6_TCLASS, &dscp_val, sizeof dscp_val);
errno = oerrno;
return sys_connect(sockfd, addr, addrlen);
}
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