manually start merging core_net

core/net/interface_linux.odin

@@ -0,0 +1,147 @@
+//+build linux, darwin, openbsd, !windows
+/*
+	Copyright 2022 Tetralux        <tetraluxonpc@gmail.com>
+	Copyright 2022 Colin Davidson  <colrdavidson@gmail.com>
+	Copyright 2022 Jeroen van Rijn <nom@duclavier.com>.
+	Made available under Odin's BSD-3 license.
+
+	List of contributors:
+		Tetralux:        Initial implementation
+		Colin Davidson:  Linux platform code, OSX platform code, Odin-native DNS resolver
+		Jeroen van Rijn: Cross platform unification, code style, documentation
+*/
+
+/*
+	Package net implements cross-platform Berkeley Sockets, DNS resolution and associated procedures.
+	For other protocols and their features, see subdirectories of this package.
+*/
+package net
+
+/*
+	This file uses `getifaddrs` libc call to enumerate interfaces.
+
+	TODO: When we have raw sockets, split off into its own file for Linux so we can use the NETLINK protocol and bypass libc.
+*/
+
+import "core:os"
+import "core:strings"
+
+/*
+	`enumerate_interfaces` retrieves a list of network interfaces with their associated properties.
+*/
+enumerate_interfaces :: proc(allocator := context.allocator) -> (interfaces: []Network_Interface, err: Network_Error) {
+	context.allocator = allocator
+
+	head: ^os.ifaddrs
+
+	if res := os._getifaddrs(&head); res < 0 {
+		return {}, .Unable_To_Enumerate_Network_Interfaces
+	}
+
+	/*
+		Unlike Windows, *nix regrettably doesn't return all it knows about an interface in one big struct.
+		We're going to have to iterate over a list and coalesce information as we go.
+	*/
+
+	ifaces: map[string]^Network_Interface
+	defer delete(ifaces)
+
+	for ifaddr := head; ifaddr != nil; ifaddr = ifaddr.next {
+		adapter_name := string(ifaddr.name)
+
+		/*
+			Check if we have seen this interface name before so we can reuse the `Network_Interface`.
+			Else, create a new one.
+		*/
+		if adapter_name not_in ifaces {
+			ifaces[adapter_name] = new(Network_Interface)
+			ifaces[adapter_name].adapter_name = strings.clone(adapter_name)
+		}
+		iface := ifaces[adapter_name]
+
+		address: Address
+		netmask: Netmask
+
+		if ifaddr.address != nil {
+			switch int(ifaddr.address.sa_family) {
+			case os.AF_INET, os.AF_INET6:
+				address = sockaddr_to_endpoint(ifaddr.address).address
+
+			case os.AF_PACKET:
+				/*
+					For some obscure reason the 64-bit `getifaddrs` calls returns a pointer to a
+					32-bit `RTNL_LINK_STATS` structure, which of course means that tx/rx byte count
+					is truncated beyond usefulness.
+
+					We're not going to retrieve stats now. Instead this serves as a reminder to use
+					the NETLINK protocol for this purpose.
+
+					But in case you were curious:
+						stats := transmute(^os.rtnl_link_stats)ifaddr.data
+						fmt.println(stats)
+				*/
+			case:
+			}
+		}
+
+		if ifaddr.netmask != nil {
+			switch int(ifaddr.netmask.sa_family) {
+			case os.AF_INET, os.AF_INET6:
+			 	netmask = Netmask(sockaddr_to_endpoint(ifaddr.netmask).address)
+			case:
+			}
+		}
+
+		if ifaddr.broadcast_or_dest != nil && .BROADCAST in ifaddr.flags {
+			switch int(ifaddr.broadcast_or_dest.sa_family) {
+			case os.AF_INET, os.AF_INET6:
+			 	broadcast := sockaddr_to_endpoint(ifaddr.broadcast_or_dest).address
+			 	append(&iface.multicast, broadcast)
+			case:
+			}
+		}
+
+		if address != nil {
+			lease := Lease{
+				address = address,
+				netmask = netmask,
+			}
+			append(&iface.unicast, lease)
+		}
+
+		/*
+			TODO: Refine this based on the type of adapter.
+		*/
+ 		state := Link_State{}
+
+ 		if .UP in ifaddr.flags {
+ 			state |= {.Up}
+ 		}
+
+ 		if .DORMANT in ifaddr.flags {
+ 			state |= {.Dormant}
+ 		}
+
+ 		if .LOOPBACK in ifaddr.flags {
+ 			state |= {.Loopback}
+ 		}
+
+		iface.link.state = state
+	}
+
+	/*
+		Free the OS structures.
+	*/
+	os._freeifaddrs(head)
+
+	/*
+		Turn the map into a slice to return.
+	*/
+	_interfaces := make([dynamic]Network_Interface, 0, allocator)
+	for _, iface in ifaces {
+		append(&_interfaces, iface^)
+		free(iface)
+	}
+
+	return _interfaces[:], {}
+}