network arp+icmp lab finished

network/start/lib/xnet/pcap_device.c

@@ -1,8 +1,52 @@
 #include <memory.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
 #include "pcap_device.h"
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+#define PCAP_MAC_ADDR_LEN    6
+
+static int mac_is_zero(const uint8_t* mac_addr) {
+    if (mac_addr == NULL) {
+        return 1;
+    }
+
+    for (int i = 0; i < PCAP_MAC_ADDR_LEN; i++) {
+        if (mac_addr[i]) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+static int read_interface_mac(const char* if_name, uint8_t* mac_addr) {
+    if ((if_name == NULL) || (mac_addr == NULL)) {
+        return -1;
+    }
+
+    int fd = socket(AF_INET, SOCK_DGRAM, 0);
+    if (fd < 0) {
+        return -1;
+    }
+
+    struct ifreq ifr;
+    memset(&ifr, 0, sizeof(ifr));
+    strncpy(ifr.ifr_name, if_name, IFNAMSIZ - 1);
+    if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
+        close(fd);
+        return -1;
+    }
+
+    memcpy(mac_addr, (uint8_t*)ifr.ifr_hwaddr.sa_data, PCAP_MAC_ADDR_LEN);
+    close(fd);
+    return 0;
+}
+
 static int load_pcap_lib() {
     return 0;
 }
@@ -110,7 +154,7 @@ static int pcap_show_list(void) {
  * @param ip 打开网卡的指定ip
  * @param 给网卡设置mac
  */
-pcap_t* pcap_device_open(const char* ip, const uint8_t * mac_addr, uint8_t poll_mode) {
+pcap_t* pcap_device_open(const char* ip, uint8_t * mac_addr, uint8_t poll_mode) {
     char err_buf[PCAP_ERRBUF_SIZE];
     struct bpf_program fp;
     bpf_u_int32 mask;
@@ -130,6 +174,32 @@ pcap_t* pcap_device_open(const char* ip, const uint8_t * mac_addr, uint8_t poll_
         return (pcap_t*)0;
     }
 
+    if (mac_addr == NULL) {
+        fprintf(stderr, "pcap_open: mac address buffer is null\n");
+        return (pcap_t*)0;
+    }
+
+    if (mac_is_zero(mac_addr)) {
+        if (read_interface_mac(name_buf, mac_addr) < 0) {
+            fprintf(stderr, "pcap_open: failed to query mac address of %s, please configure it manually.\n", name_buf);
+            return (pcap_t*)0;
+        }
+        printf("pcap_open: detected mac %02x:%02x:%02x:%02x:%02x:%02x on %s\n",
+               mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5],
+               name_buf);
+        fflush(stdout);
+    } else {
+        if (read_interface_mac(name_buf, mac_addr) < 0) {
+            printf("pcap_open: failed to query mac, using configured value %02x:%02x:%02x:%02x:%02x:%02x\n",
+                   mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
+            fflush(stdout);
+        } else {
+            printf("pcap_open: overriding configured mac with detected value %02x:%02x:%02x:%02x:%02x:%02x\n",
+                   mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
+            fflush(stdout);
+        }
+    }
+
     if (pcap_lookupnet(name_buf, &net, &mask, err_buf) == -1) {
         printf("pcap_open: can't find use net card: %s\n", name_buf);
         net = 0;
@@ -166,6 +236,8 @@ pcap_t* pcap_device_open(const char* ip, const uint8_t * mac_addr, uint8_t poll_
             "(ether dst %02x:%02x:%02x:%02x:%02x:%02x or ether broadcast) and (not ether src %02x:%02x:%02x:%02x:%02x:%02x)",
             mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5],
             mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
+    printf("pcap_open: BPF filter: %s\n", filter_exp);
+    fflush(stdout);
     if (pcap_compile(pcap, &fp, filter_exp, 0, net) == -1) {
         printf("pcap_open: couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(pcap));
         return (pcap_t*)0;
@@ -174,6 +246,8 @@ pcap_t* pcap_device_open(const char* ip, const uint8_t * mac_addr, uint8_t poll_
         printf("pcap_open: couldn't install filter %s: %s\n", filter_exp, pcap_geterr(pcap));
         return (pcap_t*)0;
     }
+    printf("pcap_open: Filter installed successfully\n");
+    fflush(stdout);
 
     return pcap;
 }
@@ -222,4 +296,3 @@ uint32_t pcap_device_read(pcap_t* pcap, uint8_t* buffer, uint32_t length) {
     fprintf(stderr, "pcap_read: reading packet failed!:%s", pcap_geterr(pcap));
     return 0;
 }
-

network/start/lib/xnet/pcap_device.h

@@ -10,7 +10,7 @@
 
 typedef void (*irq_handler_t)(void* arg, uint8_t is_rx, const uint8_t* data, uint32_t size);
 
-pcap_t* pcap_device_open(const char* ip, const uint8_t *mac_addr, uint8_t poll_mode);
+pcap_t* pcap_device_open(const char* ip, uint8_t *mac_addr, uint8_t poll_mode);
 void pcap_device_close(pcap_t* pcap);
 uint32_t pcap_device_send(pcap_t* pcap, const uint8_t* buffer, uint32_t length);
 uint32_t pcap_device_read(pcap_t* pcap, uint8_t* buffer, uint32_t length);