ffi/netinfo: new module to retrieve network information

Avoid using unsupported ioctls on macOS, plus some additional tweak to support more configurations:

- uses `getifaddrs()` results to retrieve the MAC address (from `AF_LINK` on macOS, `AF_PACKET` on Linux),
  instead of the Linux specific `SIOCGIFHWADDR` ioctl
- for checking the interface is wireless on Linux: do a filesystem check for `/sys/class/net/$IFACE/wireless/`,
  instead of using the `SIOCGIWNAME` ioctl, which is not always supported (it depends on the driver: no dice
  on my Kindle PW2, or with the `mac80211_hwsim` module to simulate wireless interfaces)
- on macOS: checking if the interface is wireless is still unsupported, as is retrieving the SSID (which is
  not possible anyway on more recent macOS versions without location permission)

Author: benoit-pierre

ffi-cdecl/posix_cdecl.c

@@ -43,11 +43,15 @@
 #include <net/if.h>
 #if defined(__APPLE__)
 # include <net/if_dl.h>
+# include <net/if_types.h>
 #endif
 #include <net/route.h>
 #include <netdb.h>
 #include <netinet/ip.h>
 #include <netinet/ip_icmp.h>
+#if defined(__linux__)
+# include <netpacket/packet.h>
+#endif
 #include <poll.h>
 #include <pthread.h>
 #if defined(__linux__)
@@ -285,11 +289,18 @@ cdecl_type(__fsfilcnt_t);
 
 cdecl_struct(statvfs);
 
+#if defined(__APPLE__)
+cdecl_const(IFT_ETHER);
+#endif
+
 cdecl_const(AF_INET);
 cdecl_const(AF_INET6);
 #if defined(__APPLE__)
 cdecl_const(AF_LINK);
 #endif
+#if defined(__linux__)
+cdecl_const(AF_PACKET);
+#endif
 cdecl_const(AF_UNIX);
 
 cdecl_const(NI_MAXHOST);
@@ -339,6 +350,9 @@ cdecl_struct(sockaddr);
 #if defined(__APPLE__)
 cdecl_struct(sockaddr_dl);
 #endif
+#if defined(__linux__)
+cdecl_struct(sockaddr_ll);
+#endif
 cdecl_struct(sockaddr_in);
 cdecl_struct(sockaddr_in6);
 cdecl_struct(sockaddr_un);
@@ -357,9 +371,7 @@ cdecl_struct(ifreq);
 
 #if defined(__linux__) && !defined(__ANDROID__)
 
-cdecl_const(SIOCGIFHWADDR);
 cdecl_const(SIOCGIWESSID);
-cdecl_const(SIOCGIWNAME);
 
 cdecl_const(IW_ENCODE_INDEX);
 cdecl_const(IW_ESSID_MAX_SIZE);

ffi-cdecl/posix_h_android_arm.lua

@@ -137,6 +137,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -178,6 +180,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  uint16_t sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;

ffi-cdecl/posix_h_android_arm64.lua

@@ -138,6 +138,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -179,6 +181,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  uint16_t sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;

ffi-cdecl/posix_h_android_x64.lua

@@ -138,6 +138,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -179,6 +181,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  uint16_t sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;

ffi-cdecl/posix_h_android_x86.lua

@@ -137,6 +137,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -178,6 +180,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  uint16_t sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;

ffi-cdecl/posix_h_linux_arm.lua

@@ -143,6 +143,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -186,6 +188,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  unsigned short sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;
@@ -254,12 +266,8 @@ struct ifreq {
     caddr_t ifru_data;
   } ifr_ifru;
 };
-// cdecl_const_SIOCGIFHWADDR
-static const unsigned SIOCGIFHWADDR = 35111;
 // cdecl_const_SIOCGIWESSID
 static const unsigned SIOCGIWESSID = 35611;
-// cdecl_const_SIOCGIWNAME
-static const unsigned SIOCGIWNAME = 35585;
 // cdecl_const_IW_ENCODE_INDEX
 static const unsigned IW_ENCODE_INDEX = 255;
 // cdecl_const_IW_ESSID_MAX_SIZE

ffi-cdecl/posix_h_linux_arm64.lua

@@ -142,6 +142,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -185,6 +187,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  unsigned short sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;
@@ -253,12 +265,8 @@ struct ifreq {
     caddr_t ifru_data;
   } ifr_ifru;
 };
-// cdecl_const_SIOCGIFHWADDR
-static const unsigned SIOCGIFHWADDR = 35111;
 // cdecl_const_SIOCGIWESSID
 static const unsigned SIOCGIWESSID = 35611;
-// cdecl_const_SIOCGIWNAME
-static const unsigned SIOCGIWNAME = 35585;
 // cdecl_const_IW_ENCODE_INDEX
 static const unsigned IW_ENCODE_INDEX = 255;
 // cdecl_const_IW_ESSID_MAX_SIZE

ffi-cdecl/posix_h_linux_x64.lua

@@ -143,6 +143,8 @@ struct statvfs {
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6
 static const unsigned AF_INET6 = 10;
+// cdecl_const_AF_PACKET
+static const unsigned AF_PACKET = 17;
 // cdecl_const_AF_UNIX
 static const unsigned AF_UNIX = 1;
 // cdecl_const_NI_MAXHOST
@@ -186,6 +188,16 @@ struct sockaddr {
   sa_family_t sa_family;
   char sa_data[14];
 };
+// cdecl_struct_sockaddr_ll
+struct sockaddr_ll {
+  unsigned short sll_family;
+  unsigned short sll_protocol;
+  int sll_ifindex;
+  unsigned short sll_hatype;
+  unsigned char sll_pkttype;
+  unsigned char sll_halen;
+  unsigned char sll_addr[8];
+};
 // cdecl_struct_sockaddr_in
 struct sockaddr_in {
   sa_family_t sin_family;
@@ -254,12 +266,8 @@ struct ifreq {
     caddr_t ifru_data;
   } ifr_ifru;
 };
-// cdecl_const_SIOCGIFHWADDR
-static const unsigned SIOCGIFHWADDR = 35111;
 // cdecl_const_SIOCGIWESSID
 static const unsigned SIOCGIWESSID = 35611;
-// cdecl_const_SIOCGIWNAME
-static const unsigned SIOCGIWNAME = 35585;
 // cdecl_const_IW_ENCODE_INDEX
 static const unsigned IW_ENCODE_INDEX = 255;
 // cdecl_const_IW_ESSID_MAX_SIZE

ffi-cdecl/posix_h_macos.lua

@@ -139,6 +139,8 @@ struct statvfs {
   unsigned long f_flag;
   unsigned long f_namemax;
 };
+// cdecl_const_IFT_ETHER
+static const unsigned IFT_ETHER = 6;
 // cdecl_const_AF_INET
 static const unsigned AF_INET = 2;
 // cdecl_const_AF_INET6