Changeset 955 for trunk/lib/format_linux.c

Timestamp:

08/28/06 14:28:16 (7 years ago)

Author:

perry

Message:

Author: Tom Young

Here is a patch to use the control message block, rather than the ioctl for
getting the time stamp. It seems to work for me. As far as i can tell, the
control block stuff has been used for ages (it looked like it was in 2.4.24)
but it should fall back to the ioctl anyway if it has to.

File:

• trunk/lib/format_linux.c (modified) (5 diffs)

trunk/lib/format_linux.c

@@ -49 +49 @@
 #include <net/if.h>
 #include <sys/ioctl.h>
+#include <errno.h>
 
 struct libtrace_format_data_t {
@@ -93 +94 @@
 {
         struct sockaddr_ll addr;
+        int one = 1;
         memset(&addr,0,sizeof(addr));
         FORMAT(libtrace->format_data)->fd = 
@@ -132 +134 @@
                                 socklen);
         }
+
+        setsockopt(FORMAT(libtrace->format_data)->fd,
+                        SOL_SOCKET,
+                        SO_TIMESTAMP,
+                        &one,
+                        sizeof(one));
 
         return 0;
@@ -202 +210 @@
 #define LIBTRACE_MIN(a,b) ((a)<(b) ? (a) : (b))
 
+/* 20 should be enough */
+#define CMSG_BUF_SIZE 20
 static int linuxnative_read_packet(libtrace_t *libtrace, libtrace_packet_t *packet) 
 {
         struct libtrace_linuxnative_header *hdr;
+        struct msghdr msghdr;
+        struct iovec iovec;
+        unsigned char controlbuf[CMSG_BUF_SIZE];
+        struct cmsghdr *cmsg;
         socklen_t socklen;
         int snaplen;
+
         if (!packet->buffer || packet->buf_control == TRACE_CTRL_EXTERNAL) {
                 packet->buffer = malloc(LIBTRACE_PACKET_BUFSIZE);
@@ -221 +236 @@
                         (int)LIBTRACE_PACKET_BUFSIZE-(int)sizeof(*hdr),
                         (int)FORMAT(libtrace->format_data)->snaplen);
-        hdr->wirelen = recvfrom(FORMAT(libtrace->format_data)->fd,
-                        (void*)packet->payload,
-                        snaplen,
-                        MSG_TRUNC,
-                        (struct sockaddr *)&hdr->hdr,
-                        &socklen);
-
-        if (hdr->wirelen==-1)
+
+        msghdr.msg_name = &hdr->hdr;
+        msghdr.msg_namelen = sizeof(struct sockaddr_ll);
+
+        msghdr.msg_iov = &iovec;
+        msghdr.msg_iovlen = 1;
+
+        msghdr.msg_control = &controlbuf;
+        msghdr.msg_controllen = CMSG_BUF_SIZE;
+        msghdr.msg_flags = 0;
+
+        iovec.iov_base = (void*)packet->payload;
+        iovec.iov_len = snaplen;
+
+        hdr->wirelen = recvmsg(FORMAT(libtrace->format_data)->fd, &msghdr, 0);
+
+        if (hdr->wirelen==-1) {
+                trace_set_err(libtrace,errno,"recvmsg");
                 return -1;
+        }
 
         hdr->caplen=LIBTRACE_MIN(snaplen,hdr->wirelen);
 
-        if (ioctl(FORMAT(libtrace->format_data)->fd,SIOCGSTAMP,&hdr->ts)==-1)
+        for (cmsg = CMSG_FIRSTHDR(&msghdr);
+                        cmsg != NULL;
+                        cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
+                if (cmsg->cmsg_level == SOL_SOCKET
+                        && cmsg->cmsg_type == SO_TIMESTAMP
+                        && cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval))) {
+                        memcpy(&hdr->ts, CMSG_DATA(cmsg),
+                                        sizeof(struct timeval));
+                        break;
+                }
+        }
+
+        if (cmsg == NULL && ioctl(FORMAT(libtrace->format_data)->fd,
+                                SIOCGSTAMP,&hdr->ts)==-1)
                 perror("ioctl(SIOCGSTAMP)");