From 8eca22db0981a42d3a9513b397d012a4c450789a Mon Sep 17 00:00:00 2001
From: hackbard <hackbard>
Date: Mon, 11 Nov 2002 23:44:07 +0000
Subject: [PATCH] added channelhopping feature

---
 hdw-sniff.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
 hdw-sniff.h |  7 +++++++
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/hdw-sniff.c b/hdw-sniff.c
index ab67722..8cbfb49 100644
--- a/hdw-sniff.c
+++ b/hdw-sniff.c
@@ -12,6 +12,9 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <pcap.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
 
 /* IEEE 802.3 stuff -- i will concentrate on .11 stuff before! */
 #include <netinet/if_ether.h>  /* for ethhdr struct */
@@ -28,6 +31,9 @@ int main(int argc, char *argv[]) {
 
 	char pcap_error[PCAP_ERRBUF_SIZE];
 	pcap_t *pcap_handle;
+	int pcap_fd;
+	fd_set pcap_fd_set;
+	struct timeval fd_set_tv;
 	char sys_call[30];
 	FILE *logfile;
 	struct info_struct my_info_struct;
@@ -69,13 +75,30 @@ int main(int argc, char *argv[]) {
 		printf("%s: %s\n",argv[0],pcap_error);
 		return 1;
 	}
+
+	/* set non blocking */
+	if((pcap_setnonblock(pcap_handle,1,pcap_error))==-1) {
+		printf("%s: %s\n",argv[0],pcap_error);
+		return 1;
+	}
 	
 	/* grab a package until user breaks */
 	my_info_struct.count=0;
 	my_info_struct.mmode=argv[2][0];
 	strcpy(my_info_struct.dev,argv[1]);
+
+	/* prepare for select */
+	pcap_fd=pcap_fileno(pcap_handle);
+	FD_ZERO(&pcap_fd_set);
+	FD_SET(pcap_fd,&pcap_fd_set);
+	fd_set_tv.tv_sec=0;
+	fd_set_tv.tv_usec=500000;
+
 	/* do loopp */
-	pcap_loop(pcap_handle,-1,pcap_process,(u_char *)&my_info_struct);
+	while(1) {
+		if((select(pcap_fd+1,&pcap_fd_set,NULL,NULL,&fd_set_tv)) && (FD_ISSET(pcap_fd,&pcap_fd_set))) pcap_loop(pcap_handle,-1,pcap_process,(u_char *)&my_info_struct);
+		else hop_channel(&my_info_struct,pcap_fd);
+	}
 	return 0;
 }
 
@@ -166,4 +189,21 @@ void pcap_process(u_char *info,const struct pcap_pkthdr *pcap_header,
 	printf("\n");
 }
 
-		
+int hop_channel(struct info_struct *info,int pcap_fd) {
+	struct iwreq my_iwreq;
+
+	if (info->channel==15) info->channel=1;
+
+	memset(&my_iwreq,0,sizeof(my_iwreq));
+	strcpy(my_iwreq.ifr_name,info->dev);
+	my_iwreq.u.freq.e=0;
+	my_iwreq.u.freq.m=info->channel;
+	if((ioctl(pcap_fd,SIOCSIWFREQ,& my_iwreq))==-1) {
+		printf("unable to hop channels\n");
+		return -1;
+	}
+	printf("debug: hopped to channel %d\n",info->channel);
+	++(info->channel);
+	return 0;
+}
+	
diff --git a/hdw-sniff.h b/hdw-sniff.h
index e7a6995..7e34dfc 100644
--- a/hdw-sniff.h
+++ b/hdw-sniff.h
@@ -1,3 +1,5 @@
+#include <linux/wireless.h>
+
 /* the pcap_process callback function */
 void pcap_process(u_char *count,const struct pcap_pkthdr *pcap_header,
 			const u_char *package);
@@ -7,4 +9,9 @@ struct info_struct {
                 int count;      /* count packages */
                 char dev[10];   /* device */
                 char mmode;     /* monitor type ... and later more */
+		int channel;	/* current freq channel */
         };
+
+/* hop_chanel function */
+int hop_channel(struct info_struct *info,int pcap_fd);
+
-- 
2.39.2