diff options
Diffstat (limited to 'src/ipcpd/udp')
| -rw-r--r-- | src/ipcpd/udp/udp.c | 57 |
1 files changed, 55 insertions, 2 deletions
diff --git a/src/ipcpd/udp/udp.c b/src/ipcpd/udp/udp.c index 168ea718..8fba5a77 100644 --- a/src/ipcpd/udp/udp.c +++ b/src/ipcpd/udp/udp.c @@ -47,6 +47,10 @@ #include <stdlib.h> #include <sys/wait.h> #include <fcntl.h> +#include <unistd.h> +#if defined(__linux__) +#include <netinet/ip.h> +#endif #define FLOW_REQ 1 #define FLOW_REPLY 2 @@ -130,6 +134,53 @@ static const char * __inet_ntop(const struct __ADDR * addr, return inet_ntop(__AF, addr, buf, __ADDRSTRLEN); } +#if defined(BUILD_IPCP_UDP4) +#define UDP_MTU_FALLBACK IPCP_UDP4_MTU +#define UDP_IP_OVERHEAD 28U /* IPv4 + UDP */ +#else +#define UDP_MTU_FALLBACK IPCP_UDP6_MTU +#define UDP_IP_OVERHEAD 48U /* IPv6 + UDP */ +#endif + +static uint32_t udp_query_mtu(const struct __SOCKADDR * saddr) +{ +#if defined(__linux__) && (defined(IP_MTU) || defined(IPV6_MTU)) + int sock; + int mtu = 0; + socklen_t len = sizeof(mtu); + + sock = socket(__AF, SOCK_DGRAM, IPPROTO_UDP); + if (sock < 0) + return UDP_MTU_FALLBACK; + + if (connect(sock, (const struct sockaddr *) saddr, + sizeof(*saddr)) < 0) + goto fallback; + +#if defined(BUILD_IPCP_UDP4) && defined(IP_MTU) + if (getsockopt(sock, IPPROTO_IP, IP_MTU, &mtu, &len) < 0) + goto fallback; +#elif defined(BUILD_IPCP_UDP6) && defined(IPV6_MTU) + if (getsockopt(sock, IPPROTO_IPV6, IPV6_MTU, &mtu, &len) < 0) + goto fallback; +#else + goto fallback; +#endif + close(sock); + + if (mtu <= (int) UDP_IP_OVERHEAD) + return UDP_MTU_FALLBACK; + + return (uint32_t) mtu - UDP_IP_OVERHEAD; + + fallback: + close(sock); +#else + (void) saddr; +#endif + return UDP_MTU_FALLBACK; +} + static int udp_data_init(void) { int i; @@ -285,7 +336,8 @@ static int udp_ipcp_port_req(struct __SOCKADDR * c_saddr, { int fd; - fd = ipcp_wait_flow_req_arr(dst, qs, IPCP_UDP_MPL, data); + fd = ipcp_wait_flow_req_arr(dst, qs, IPCP_UDP_MPL, + udp_query_mtu(c_saddr), data); if (fd < 0) { log_err("Could not get new flow from IRMd."); return -1; @@ -332,7 +384,8 @@ static int udp_ipcp_port_alloc_reply(const struct __SOCKADDR * saddr, pthread_rwlock_unlock(&udp_data.flows_lock); - if (ipcp_flow_alloc_reply(s_eid, response, mpl, data) < 0) { + if (ipcp_flow_alloc_reply(s_eid, response, mpl, + udp_query_mtu(saddr), data) < 0) { log_err("Failed to reply to flow allocation."); return -1; } |