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udp epoll

#define _GNU_SOURCE 1

 

#include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <errno.h> #include <sys/timerfd.h> #include <sys/epoll.h> #include <sys/types.h> #include <netinet/in.h> #include <unistd.h> #define ADDR  INADDR_LOOPBACK #define PORT  34567 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0])) #define SAVE_ERRNO(block) do { int errno_ = errno; { block; } errno = errno_; } while (0) typedef struct {   int fd;   unsigned int readable:1;   unsigned int writable:1; } peer_t; static int tmfd = -1; static int epfd = -1; static int npeers; static unsigned long bytes_read; static unsigned long bytes_written; static void do_report(void) {   printf(     "=====================\n"     "%lu bytes read\n"     "%lu bytes written\n",     bytes_read, bytes_written);   bytes_read = 0;   bytes_written = 0; } static int do_close(int fd) {   int r;   do     r = close(fd);   while (r == -1 && errno == EINTR);   return r; } static int add_fd(int fd, void *arg, int events) {   struct epoll_event ee = { .data.ptr = arg, .events = events | EPOLLET };   return epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ee); } static int make_sock_fd(unsigned short port) {   struct sockaddr_in sin;   int sockfd;   if ((sockfd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0)) == -1)     return -1;   memset(&sin, 0, sizeof sin);   sin.sin_addr.s_addr = htonl(ADDR);   sin.sin_port = htons(port);   sin.sin_family = AF_INET;   if (bind(sockfd, (struct sockaddr *) &sin, sizeof sin) == -1)     return -1;   return sockfd; } static int make_timer_fd(unsigned int ms) {   struct itimerspec its;   if ((tmfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) == -1)     return -1; #define SET_TS(ts, ms) ((ts)->tv_sec = (ms) / 1000, (ts)->tv_nsec = ((ms) % 1000) * 1e6)   SET_TS(&its.it_interval, ms);   SET_TS(&its.it_value, ms);   if (timerfd_settime(tmfd, 0, &its, NULL)) {     SAVE_ERRNO(do_close(tmfd));     return -1;   }   return tmfd; } static int do_recv(int fd) {   char buf[1024];   ssize_t r;   do     r = read(fd, buf, sizeof buf);   while (r == -1 && errno == EINTR);   if (r > 0)     bytes_read += r;   return r; } static int do_send(int fd, const void *data, size_t size) {   struct sockaddr_in sin;   ssize_t r;   static int port = PORT;   port = PORT + (((port - PORT) + 1) % npeers);   sin.sin_family = AF_INET;   sin.sin_addr.s_addr = htonl(ADDR);   sin.sin_port = htons(port);   do     r = sendto(fd, data, size, 0, (struct sockaddr *) &sin, sizeof sin);   while (r == -1 && errno == EINTR);   if (r > 0)     bytes_written += r;   return r; } static int do_epoll(void) {   struct epoll_event out[1024];   peer_t *peer;   int i, n, r;   int events;   int fd;   do     n = epoll_wait(epfd, out, ARRAY_SIZE(out), -1);   while (n == -1 && errno == EINTR);   if (n == -1)     return -1;   for (i = 0; i < n; i++) {     events = out[i].events;     peer = out[i].data.ptr;     fd = peer->fd;     if (events & ~(EPOLLIN|EPOLLOUT))       return -1;     if (fd == tmfd) {       char buf[8];       read(fd, buf, 8);       do_report();       continue;     }     if (peer->readable && (events & EPOLLIN)) {       if ((r = do_recv(fd)) == -1)         return -1;       else         peer->readable = 0, peer->writable = 1;     }     if (peer->writable  && (events & EPOLLOUT)) {       const char reply[] = "PING";       if ((r = do_send(fd, reply, sizeof(reply) - 1)) == -1)         return -1;       else         peer->readable = 1, peer->writable = 0;     }   }   return 0; } int main(int argc, char **argv) {   peer_t *peers;   peer_t tmp;   int i, r;   (void) argc;   if (argv[1] == NULL || (npeers = atoi(argv[1])) == 0)     npeers = 100;   if ((epfd = epoll_create1(EPOLL_CLOEXEC)) == -1) {     perror("make_epoll_fd");     exit(1);   }   if ((tmfd = make_timer_fd(2000)) == -1) {     perror("make_timer_fd");     exit(1);   }   tmp.fd = tmfd;   if (add_fd(tmfd, &tmp, EPOLLIN)) {     perror("add_fd");     exit(1);   }   if ((peers = calloc(npeers, sizeof(peers[0]))) == NULL) {     perror("malloc");     exit(1);   }   for (i = 0; i < npeers; i++) {     peers[i].readable = 0;     peers[i].writable = 1;     if ((peers[i].fd = make_sock_fd(PORT + i)) == -1)       perror("make_sock_fd");     else if (add_fd(peers[i].fd, &peers[i], EPOLLIN|EPOLLOUT))       perror("add_fd");   }   while ((r = do_epoll()) == 0)     /* nop */ ;   if (r == -1) {     perror("do_epoll");     exit(1);   }   return 0;

 

 

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