From cac8f382588e33c83f533936ba980ed06d4340aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Wed, 1 Dec 2021 22:10:39 +0100
Subject: Network: automatically find broadcast addresses
---
src/Network/ifaddrs.c | 41 +++++++++++++++++++++++++++++++++++++++++
src/Network/ifaddrs.h | 3 +++
2 files changed, 44 insertions(+)
create mode 100644 src/Network/ifaddrs.c
create mode 100644 src/Network/ifaddrs.h
(limited to 'src/Network')
diff --git a/src/Network/ifaddrs.c b/src/Network/ifaddrs.c
new file mode 100644
index 0000000..37c3e00
--- /dev/null
+++ b/src/Network/ifaddrs.c
@@ -0,0 +1,41 @@
+#include "ifaddrs.h"
+
+#include <arpa/inet.h>
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <endian.h>
+
+uint32_t * broadcast_addresses(void)
+{
+ struct ifaddrs * addrs;
+ if (getifaddrs(&addrs) < 0)
+ return 0;
+
+ size_t capacity = 16, count = 0;
+ uint32_t * ret = malloc(sizeof(uint32_t) * capacity);
+
+ for (struct ifaddrs * ifa = addrs; ifa; ifa = ifa->ifa_next) {
+ if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET &&
+ ifa->ifa_flags & IFF_BROADCAST) {
+ if (count + 2 >= capacity) {
+ capacity *= 2;
+ uint32_t * nret = realloc(ret, sizeof(uint32_t) * capacity);
+ if (nret) {
+ ret = nret;
+ } else {
+ free(ret);
+ return 0;
+ }
+ }
+
+ ret[count] = ((struct sockaddr_in*)ifa->ifa_broadaddr)->sin_addr.s_addr;
+ count++;
+ }
+ }
+
+ freeifaddrs(addrs);
+ ret[count] = 0;
+ return ret;
+}
diff --git a/src/Network/ifaddrs.h b/src/Network/ifaddrs.h
new file mode 100644
index 0000000..06d26ec
--- /dev/null
+++ b/src/Network/ifaddrs.h
@@ -0,0 +1,3 @@
+#include <stdint.h>
+
+uint32_t * broadcast_addresses(void);
--
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