增加 pcap 示例代码

programthink · programthink · commit 3190b9f94d52 · 2015-07-23T23:56:08.000+08:00
diff --git a/libs/cpp.wiki b/libs/cpp.wiki
@@ -1177,6 +1177,63 @@ Wikipedia：[https://en.wikipedia.org/wiki/Pcap 英文]
 
 很著名的 Sniffer 抓包库，基于 C 语言开发。
 
+代码示例——一个简单的抓包示例
+<source lang="cpp">
+&#35;include <stdio.h>
+&#35;include <pcap.h>
+
+int main(int argc, char* argv[])
+{
+    pcap_t* handle;            /* Session handle */
+    char* dev;            /* The device to sniff on */
+    char errbuf[PCAP_ERRBUF_SIZE];    /* Error string */
+    struct bpf_program fp;        /* The compiled filter */
+    char filter_exp[] = "port 23";    /* The filter expression */
+    bpf_u_int32 mask;        /* Our netmask */
+    bpf_u_int32 net;        /* Our IP */
+    struct pcap_pkthdr header;    /* The header that pcap gives us */
+    const u_char* packet;        /* The actual packet */
+
+    /* Define the device */
+    dev = pcap_lookupdev(errbuf);
+    if(dev == NULL)
+    {
+        fprintf(stderr, "Couldn't find default device: %s\n", errbuf);
+        return 2;
+    }
+    /* Find the properties for the device */
+    if(pcap_lookupnet(dev, &net, &mask, errbuf) == -1)
+    {
+        fprintf(stderr, "Couldn't get netmask for device %s: %s\n", dev, errbuf);
+        net = 0;
+        mask = 0;
+    }
+    /* Open the session in promiscuous mode */
+    handle = pcap_open_live(dev, BUFSIZ, 1, 1000, errbuf);
+    if(handle == NULL)
+    {
+        fprintf(stderr, "Couldn't open device %s: %s\n", dev, errbuf);
+        return 2;
+    }
+    /* Compile and apply the filter */
+    if(pcap_compile(handle, &fp, filter_exp, 0, net) == -1)
+    {
+        fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
+        return 2;
+    }
+    if(pcap_setfilter(handle, &fp) == -1)
+    {
+        fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
+        return 2;
+    }
+
+    packet = pcap_next(handle, &header);  /* Grab a packet */
+    printf("Jacked a packet with length of [%d]\n", header.len);
+    pcap_close(handle);  /* Close the session */
+    return 0;
+}
+</source>
+
 <h4>WinPcap</h4>
 
 Home：[http://www.winpcap.org/]
