File nmap-4.00-libpcap-filter.diff of Package nmap

Index: libpcap/pcap-bpf.c
===================================================================
--- libpcap/pcap-bpf.c.orig
+++ libpcap/pcap-bpf.c
@@ -449,7 +449,7 @@ bpf_open(pcap_t *p)
 		fd = open(device, O_RDWR);
 		if (fd == -1 && errno == EACCES)
 			fd = open(device, O_RDONLY);
-	} while (fd < 0 && errno == EBUSY);
+	} while (fd < 0 && errno == EBUSY && n < 1000);
 
 	/*
 	 * XXX better message for all minors used
Index: libpcap/pcap-linux.c
===================================================================
--- libpcap/pcap-linux.c.orig
+++ libpcap/pcap-linux.c
@@ -1232,8 +1232,30 @@ pcap_setfilter_linux(pcap_t *handle, str
 	if (can_filter_in_kernel) {
 		if ((err = set_kernel_filter(handle, &fcode)) == 0)
 		{
+			char buf[1024];
+			int oldflags;
+			int ret;
+			unsigned int received = 0, rec_len = 0;
+			socklen_t optlen = sizeof(rec_len);
 			/* Installation succeded - using kernel filter. */
 			handle->md.use_bpf = 1;
+
+			oldflags = fcntl(handle->fd, F_GETFL, 0);
+			oldflags |= O_NONBLOCK;
+			fcntl(handle->fd, F_SETFL, oldflags);
+			getsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
+				   (char *)&rec_len, &optlen);
+
+                        /* now read all packets received until now */
+			while((ret = read(handle->fd, buf, 1024)) > 0
+			      && received < rec_len) {
+			    received += ret;
+			}
+
+			if(oldflags > 0) {
+			    oldflags &= ~O_NONBLOCK;
+			    fcntl(handle->fd, F_SETFL, oldflags);
+			}
 		}
 		else if (err == -1)	/* Non-fatal error */
 		{