Support to set a MAC address on an interface

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 jobs:
   build:
     macos:
-      xcode: "12.5.1"
+      xcode: "14.2.0"
 
     steps:
       - checkout

README.md

@@ -76,7 +76,7 @@ The modules that are currently defined are given below:
 - hypervisor : General hypervisor management 
 - bridge : bridges management 
 - iol_bridge : IOL (IOS on Linux) bridges management 
-- docker : Docker veth management 
+- docker : Docker management 
 - brctl : Linux bridge management
 
 ### Hypervisor module ("hypervisor")
@@ -414,6 +414,14 @@ docker move_to_ns guestif 6367 eth0
 100-guestif moved to namespace 6367
 ```
 
+- **docker set_mac_addr** *\<interface\>* *\<mac_addr\>*
+    *\<mac_addr\>*: Set a MAC address on an interface.
+
+``` {.bash}
+docker set_mac_addr tap-gns3-e0 12:34:56:78:12:42
+100-MAC address 12:34:56:78:12:42" has been successfully set on interface tap-gns3-e0
+```
+
 - **docker delete_veth** *\<interface_name\>*: Delete virtual
     Ethernet interface.
 

src/hypervisor_docker.c

@@ -44,6 +44,7 @@
 #include <linux/if_bridge.h>
 #include <sched.h>
 #include <linux/ethtool.h>
+#include <regex.h>
 
 #include "ubridge.h"
 #include "hypervisor.h"
@@ -308,11 +309,67 @@ static int cmd_move_ns(hypervisor_conn_t *conn, int argc, char *argv[])
 	return err;
 }
 
+static int cmd_set_mac_addr(hypervisor_conn_t *conn, int argc, char *argv[])
+{
+    int fd;
+    struct ifreq ifr;
+    char *interface = argv[0];
+    char mac_char[18];
+    regex_t regex;
+
+    if (strlen(interface) >= IFNAMSIZ) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "interface name is too long");
+        return (-1);
+    }
+
+    if (regcomp(&regex, "^([0-9A-Fa-f]{2}:){5}([0-9A-Fa-f]{2})$", REG_EXTENDED)) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "could not compile regex");
+        return (-1);
+    }
+
+    if (regexec(&regex, argv[1], 0, NULL, 0)) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "invalid MAC address format");
+        regfree(&regex);
+        return (-1);
+    }
+    regfree(&regex);
+
+    strncpy(mac_char, argv[1], 17);
+    mac_char[17] = '\0';
+    sscanf(mac_char, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+        &ifr.ifr_hwaddr.sa_data[0],
+        &ifr.ifr_hwaddr.sa_data[1],
+        &ifr.ifr_hwaddr.sa_data[2],
+        &ifr.ifr_hwaddr.sa_data[3],
+        &ifr.ifr_hwaddr.sa_data[4],
+        &ifr.ifr_hwaddr.sa_data[5]
+        );
+
+    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+      hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "could not create socket: %s", strerror(errno));
+      return (-1);
+    }
+
+    strncpy(ifr.ifr_name, interface, IFNAMSIZ);
+    ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
+
+    if (ioctl(fd, SIOCSIFHWADDR, &ifr) < 0) {
+      hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "could not set a MAC address on interface %s", interface);
+      close(fd);
+      return (-1);
+    }
+
+    hypervisor_send_reply(conn, HSC_INFO_OK, 1, "MAC address %s has been successfully set on interface %s", mac_char, interface);
+    close(fd);
+    return (0);
+}
+
 /* Docker commands */
 static hypervisor_cmd_t docker_cmd_array[] = {
    { "create_veth", 2, 2, cmd_create_veth_pair, NULL },
    { "delete_veth", 1, 1, cmd_delete_veth, NULL },
    { "move_to_ns", 3, 3, cmd_move_ns, NULL },
+   { "set_mac_addr", 2, 2, cmd_set_mac_addr, NULL },
    { NULL, -1, -1, NULL, NULL },
 };