Add network speed functions

Makefile

@@ -16,6 +16,7 @@ COM =\
 	components/kernel_release\
 	components/keyboard_indicators\
 	components/load_avg\
+	components/netspeeds\
 	components/num_files\
 	components/ram\
 	components/run_command\

README

@@ -19,6 +19,7 @@ Features
 - Kernel version
 - Keyboard indicators
 - Load average
+- Network speeds (RX and TX)
 - Number of files in a directory (hint: Maildir)
 - Memory status (free memory, percentage, total memory and used memory)
 - Swap status (free swap, percentage, total swap and used swap)

components/netspeeds.c

@@ -0,0 +1,53 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <limits.h>
+
+#include "../util.h"
+
+#if defined(__linux__)
+	const char *
+	netspeed_rx(const char *interface)
+	{
+		static int valid;
+		static unsigned long long rxbytes;
+		unsigned long oldrxbytes;
+		extern const unsigned int interval;
+		char path[PATH_MAX];
+
+		oldrxbytes = rxbytes;
+		snprintf(path, sizeof(path), "/sys/class/net/%s/statistics/rx_bytes", interface);
+		if (pscanf(path, "%llu", &rxbytes) != 1) {
+			return NULL;
+		}
+		if (!valid) {
+			valid = 1;
+			return NULL;
+		}
+
+		return fmt_scaled((rxbytes - oldrxbytes) / interval * 1000);
+	}
+
+	const char *
+	netspeed_tx(const char *interface)
+	{
+		static int valid;
+		static unsigned long long txbytes;
+		unsigned long oldtxbytes;
+		extern const unsigned int interval;
+		char path[PATH_MAX];
+
+		oldtxbytes = txbytes;
+		snprintf(path, sizeof(path), "/sys/class/net/%s/statistics/tx_bytes", interface);
+		if (pscanf(path, "%llu", &txbytes) != 1) {
+			return NULL;
+		}
+		if (!valid) {
+			valid = 1;
+			return NULL;
+		}
+
+		return fmt_scaled((txbytes - oldtxbytes) / interval * 1000);
+	}
+#elif defined(__OpenBSD__)
+	/* unimplemented */
+#endif

slstatus.h

@@ -37,6 +37,10 @@ const char *keyboard_indicators(void);
 /* load_avg */
 const char *load_avg(const char *);
 
+/* netspeeds */
+const char *netspeed_rx(const char *);
+const char *netspeed_tx(const char *);
+
 /* num_files */
 const char *num_files(const char *);