diff options
Diffstat (limited to 'udp.c')
| -rw-r--r-- | udp.c | 60 |
1 files changed, 60 insertions, 0 deletions
@@ -110,6 +110,7 @@ #include <sys/socket.h> #include <sys/uio.h> #include <time.h> +#include <linux/errqueue.h> #include "checksum.h" #include "util.h" @@ -729,6 +730,59 @@ static void udp_tap_prepare(const struct ctx *c, const struct mmsghdr *mmh, } /** + * udp_sock_recverr() - Receive and clear an error from a socket + * @s: Socket to receive from + * + * Return: true if errors received and processed, false if no more errors + * + * #syscalls recvmsg + */ +static bool udp_sock_recverr(int s) +{ + const struct sock_extended_err *ee; + const struct cmsghdr *hdr; + char buf[CMSG_SPACE(sizeof(*ee))]; + struct msghdr mh = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_iov = NULL, + .msg_iovlen = 0, + .msg_control = buf, + .msg_controllen = sizeof(buf), + }; + ssize_t rc; + + rc = recvmsg(s, &mh, MSG_ERRQUEUE); + if (rc < 0) { + if (errno != EAGAIN && errno != EWOULDBLOCK) + err_perror("Failed to read error queue"); + return false; + } + + if (!(mh.msg_flags & MSG_ERRQUEUE)) { + err("Missing MSG_ERRQUEUE flag reading error queue"); + return false; + } + + hdr = CMSG_FIRSTHDR(&mh); + if (!((hdr->cmsg_level == IPPROTO_IP && + hdr->cmsg_type == IP_RECVERR) || + (hdr->cmsg_level == IPPROTO_IPV6 && + hdr->cmsg_type == IPV6_RECVERR))) { + err("Unexpected cmsg reading error queue"); + return false; + } + + ee = (const struct sock_extended_err *)CMSG_DATA(hdr); + + /* TODO: When possible propagate and otherwise handle errors */ + debug("%s error on UDP socket %i: %s", + str_ee_origin(ee), s, strerror(ee->ee_errno)); + + return true; +} + +/** * udp_sock_recv() - Receive datagrams from a socket * @c: Execution context * @s: Socket to receive from @@ -751,6 +805,12 @@ static int udp_sock_recv(const struct ctx *c, int s, uint32_t events, ASSERT(!c->no_udp); + /* Clear any errors first */ + if (events & EPOLLERR) { + while (udp_sock_recverr(s)) + ; + } + if (!(events & EPOLLIN)) return 0; |