Attachment 203071 Details for Bug 236737 – udp recvmsg with IP_RECVDSTADDR, IP_RECVTTL and IP_RECVIF setsockopts enabled

udp recvmsg with IP_RECVDSTADDR, IP_RECVTTL and IP_RECVIF setsockopts enabled

file_236737.txt (text/plain), 2.61 KB, created by Yuval Pavel Zholkover on 2019-03-23 17:14:17 UTC

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Creator: Yuval Pavel Zholkover

Created: 2019-03-23 17:14:17 UTC

Size: 2.61 KB

patch

obsolete

>/*
>FreeBSD i386 12.0-RELEASE
>controllen: 100
>recvd: 3 bytes controllen is 100
>0 len: 16 level: 0 type: 7 msg offsets: [0,16]
>1 len: 13 level: 0 type: 65 msg offsets: [16,29]
>2 len: 68 level: 0 type: 20 msg offsets: [32,100]
>
>FreeBSD AMD64 COMPAT_FREEBSD32 12.0-RELEASE-p3
>controllen: 100
>recvd: 3 bytes controllen is 97 <-- should have been 100
>0 len: 16 level: 0 type: 7 msg offsets: [0,16]
>1 len: 13 level: 0 type: 65 msg offsets: [16,29]
>2 len: 68 level: 0 type: 20 msg offsets: [32,100]
> */
>
>#include <string.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <signal.h>
>#include <sys/types.h>
>#include <sys/socket.h>
>#include <netinet/in.h>
>#include <arpa/inet.h>
>#include <net/if_dl.h>
>
>static struct sockaddr_in loc_addr;
>static int s;
>
>static void alarm_handler(int signo) {
>  char buf[] = {0x1, 0x2, 0x3};
>  sendto(s, buf, sizeof buf, 0, (struct sockaddr*)&loc_addr, sizeof loc_addr);
>}
>
>int main(int argc, char *argv[]) {
>  memset(&loc_addr, 0, sizeof loc_addr);
>  loc_addr.sin_family = AF_INET;
>  loc_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
>  loc_addr.sin_port = htons(7777);
>  s = socket(AF_INET, SOCK_DGRAM, 0);
>  bind(s, (struct sockaddr *)&loc_addr, sizeof loc_addr);
>
>  int enable = 1;
>  setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, &enable, sizeof enable);
>  setsockopt(s, IPPROTO_IP, IP_RECVTTL, &enable, sizeof enable);
>  setsockopt(s, IPPROTO_IP, IP_RECVIF, &enable, sizeof enable);
>
>  struct msghdr h;
>  char buf[16];
>  struct iovec in[] = {{buf, sizeof buf}};
>  memset(&h, 0, sizeof h);
>  h.msg_iov = in;
>  h.msg_iovlen = 1;
>  h.msg_controllen = CMSG_SPACE(sizeof(struct in_addr)) /*IP_RECVDSTADDR*/ 
>    + CMSG_SPACE(sizeof(u_char)) /*IP_RECVTTL*/
>    + CMSG_SPACE(sizeof(struct sockaddr_dl)); /*IP_RECVIF*/
>  h.msg_control = calloc(0, h.msg_controllen);
>
>  printf("controllen: %d\n", h.msg_controllen);
>  alarm(1);
>  struct sigaction sig = {};
>  sig.sa_handler = alarm_handler;
>  sig.sa_flags = SA_RESTART;
>  sigaction(SIGALRM, &sig, NULL);
>  ssize_t recvd = recvmsg(s, &h, 0);
>  printf("recvd: %zd bytes controllen is %d\n", recvd, h.msg_controllen);
>  if (recvd < 0) {
>    perror("recvmsg failed:");
>    exit(-1);
>  }
>
>  struct cmsghdr* cmsg = NULL;
>  int i = 0;
>  while((cmsg = CMSG_NXTHDR(&h, cmsg)) != NULL) {
>    if (cmsg->cmsg_len == 0) {
>      break;
>    }
>    int first_byte = (void*)cmsg - h.msg_control;
>    int last_byte = first_byte + cmsg->cmsg_len;
>    printf("%d len: %d level: %d type: %d msg offsets: [%d,%d]\n",
>           i++, cmsg->cmsg_len, cmsg->cmsg_level, cmsg->cmsg_type, first_byte, last_byte);
>  }
>
>  return 0;
>}

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