make default gateway information accessible

* gw_iface prints the interface having a default gateway
* gw_ip prints the gatway's ip
* if_gw jumps if no default gateway exists
* when there are multiple gateways, gw_iface and gw_ip
  only print "multiple" when they are different (allows
  basic debugging of ones networking setup)


git-svn-id: https://conky.svn.sourceforge.net/svnroot/conky/trunk/conky1@1031 7f574dfc-610e-0410-a909-a81674777703

doc/conky.1

@@ -756,6 +756,14 @@ File system used space
 \fB\*(T<\fBgoto\fR\*(T>\fR \*(T<\fBx\fR\*(T> 
 The next element will be printed at position 'x'.
 
+.TP 
+\fB\*(T<\fBgw_iface\fR\*(T>\fR 
+Displays the default route's interface or "multiple"/"none" accordingly.
+
+.TP 
+\fB\*(T<\fBgw_ip\fR\*(T>\fR 
+Displays the default gateway's IP or "multiple"/"none" accordingly.
+
 .TP 
 \fB\*(T<\fBhddtemp\fR\*(T>\fR \*(T<\fBdev, (host,(port))\fR\*(T> 
 Displays temperature of a selected hard disk drive as reported by the hddtemp daemon running on host:port.
@@ -861,6 +869,10 @@ if PROCESS is running, display everything $if_running and the matching $endif
 \fB\*(T<\fBif_existing\fR\*(T>\fR \*(T<\fBfile (string)\fR\*(T> 
 if FILE exists, display everything between if_existing and the matching $endif. The optional second paramater checks for FILE containing the specified string and prints everything between $if_existing and the matching $endif.
 
+.TP 
+\fB\*(T<\fBif_gw\fR\*(T>\fR 
+if at least one default gateway exists, display everything between $if_gw and the matching $endif
+
 .TP 
 \fB\*(T<\fBif_mounted\fR\*(T>\fR \*(T<\fB(mountpoint)\fR\*(T> 
 if MOUNTPOINT is mounted, display everything between $if_mounted and the matching $endif

doc/variables.xml

@@ -839,6 +839,24 @@
 		<para></para></listitem>
 </varlistentry>
 
+<varlistentry>
+	<term>
+		<command><option>gw_iface</option></command>
+	</term>
+	<listitem>
+		Displays the default route's interface or "multiple"/"none" accordingly.
+		<para></para></listitem>
+</varlistentry>
+
+<varlistentry>
+	<term>
+		<command><option>gw_ip</option></command>
+	</term>
+	<listitem>
+		Displays the default gateway's IP or "multiple"/"none" accordingly.
+		<para></para></listitem>
+</varlistentry>
+
 <varlistentry>
 	<term>
 		<command><option>hddtemp</option></command>
@@ -1071,6 +1089,15 @@
 	<para></para></listitem>
 </varlistentry>
 
+<varlistentry>
+	<term>
+		<command><option>if_gw</option></command>
+	</term>
+	<listitem>
+		if there is at least one default gateway, display everything between $if_gw and the matching $endif
+	<para></para></listitem>
+</varlistentry>
+
 <varlistentry>
 	<term>
 		<command><option>if_running</option></command>

src/common.c

@@ -311,6 +311,9 @@ void update_stuff()
 	if (NEED(INFO_USERS)) {
 		update_users();
 	}
+	if (NEED(INFO_GW)) {
+		update_gateway_info();
+	}
 }
 
 int round_to_int(float f)

src/conky.c

@@ -1144,6 +1144,9 @@ enum text_object_type {
 	OBJ_ibm_volume,
 	OBJ_ibm_brightness,
 	OBJ_if_up,
+	OBJ_if_gw,
+	OBJ_gw_iface,
+	OBJ_gw_ip,
 	OBJ_pb_battery,
 	OBJ_voltage_mv,
 	OBJ_voltage_v,
@@ -2047,6 +2050,20 @@ static void free_text_objects(unsigned int count, struct text_object *objs)
 				free(objs[i].data.ifblock.s);
 				free(objs[i].data.ifblock.str);
 				break;
+			case OBJ_if_gw:
+				free(objs[i].data.ifblock.s);
+				free(objs[i].data.ifblock.str);
+			case OBJ_gw_iface:
+			case OBJ_gw_ip:
+				if (info.gw_info.iface) {
+					free(info.gw_info.iface);
+					info.gw_info.iface = 0;
+				}
+				if (info.gw_info.ip) {
+					free(info.gw_info.ip);
+					info.gw_info.ip = 0;
+				}
+				break;
 #endif
 #ifdef XMMS2
 			case OBJ_xmms2_artist:
@@ -2452,6 +2469,13 @@ static struct text_object *construct_text_object(const char *s,
 		blockstart[blockdepth] = object_count;
 		obj->data.ifblock.pos = object_count + 2;
 		blockdepth++;
+	END OBJ(if_gw, 0)
+		if (blockdepth >= MAX_IF_BLOCK_DEPTH) {
+			CRIT_ERR("MAX_IF_BLOCK_DEPTH exceeded");
+		}
+		blockstart[blockdepth] = object_count;
+		obj->data.ifblock.pos = object_count + 2;
+		blockdepth++;
 	END OBJ(pb_battery, 0)
 		if (arg && strcmp(arg, "status") == 0) {
 			obj->data.i = PB_BATT_STATUS;
@@ -3455,6 +3479,9 @@ static struct text_object *construct_text_object(const char *s,
 	END OBJ(user_times, INFO_USERS)
 	END OBJ(user_terms, INFO_USERS)
 	END OBJ(user_number, INFO_USERS)
+	END OBJ(gw_iface, INFO_GW)
+	END OBJ(gw_ip, INFO_GW)
+	END OBJ(if_gw, INFO_GW)
 #ifndef __OpenBSD__
 	END OBJ(adt746xcpu, 0)
 	END OBJ(adt746xfan, 0)
@@ -4387,6 +4414,20 @@ static void generate_text_internal(char *p, int p_max_size,
 					if_jumped = 0;
 				}
 			}
+			OBJ(if_gw) {
+				if (!cur->gw_info.count) {
+					i = obj->data.ifblock.pos;
+					if_jumped = 1;
+				} else {
+					if_jumped = 0;
+				}
+			}
+			OBJ(gw_iface) {
+				snprintf(p, p_max_size, "%s", cur->gw_info.iface);
+			}
+			OBJ(gw_ip) {
+				snprintf(p, p_max_size, "%s", cur->gw_info.ip);
+			}
 			OBJ(pb_battery) {
 				get_powerbook_batt_info(p, p_max_size, obj->data.i);
 			}

src/conky.h

@@ -252,6 +252,12 @@ struct usr_info {
 	int number;
 };
 
+struct gateway_info {
+	char *iface;
+	char *ip;
+	int count;
+};
+
 #ifdef TCP_PORT_MONITOR
 #include "libtcp-portmon.h"
 #define MAX_PORT_MONITOR_CONNECTIONS_DEFAULT 256
@@ -299,6 +305,7 @@ enum {
 	INFO_SMAPI = 25,
 #endif
 	INFO_USERS = 26,
+	INFO_GW = 27
 };
 
 /* get_battery_stuff() item selector */
@@ -361,6 +368,7 @@ struct information {
 	struct bmpx_s bmpx;
 #endif
 	struct usr_info users;
+	struct gateway_info gw_info;
 	struct process *cpu[10];
 	struct process *memu[10];
 	struct process *first_process;
@@ -537,6 +545,8 @@ char get_voltage(char *, size_t, char *, int, unsigned int);	/* ptarjan */
 void update_load_average();
 int interface_up(const char *dev);
 
+void update_gateway_info(void);
+
 int open_sysfs_sensor(const char *dir, const char *dev, const char *type, int n,
 	int *div, char *devtype);
 

src/linux.c

@@ -51,6 +51,8 @@
 #include <netinet/in.h>
 #include <linux/sockios.h>
 #include <net/if.h>
+#include <arpa/inet.h>
+#include <linux/route.h>
 #include <math.h>
 
 #ifdef HAVE_IWLIB
@@ -188,6 +190,62 @@ int interface_up(const char *dev)
 	return 0;
 }
 
+#define COND_FREE(x) if(x) free(x); x = 0
+#define SAVE_SET_STRING(x, y) \
+	if (x && strcmp((char *)x, (char *)y)) { \
+		free(x); \
+		x = strdup("multiple"); \
+	} else if (!x) { \
+		x = strdup(y); \
+	}
+
+void update_gateway_info()
+{
+	FILE *fp;
+	struct in_addr ina;
+	char iface[64];
+	unsigned long dest, gate, mask;
+	unsigned int flags;
+	short ref, use, metric, mtu, win, irtt;
+
+	struct gateway_info *gw_info = &info.gw_info;
+
+	COND_FREE(gw_info->iface);
+	COND_FREE(gw_info->ip);
+	gw_info->count = 0;
+
+	if ((fp = fopen("/proc/net/route", "r")) == NULL) {
+		perror("fopen()");
+		goto FAIL;
+	}
+	if (fscanf(fp, "%*[^\n]\n") == EOF) {
+		perror("fscanf()");
+		goto CLOSE_FAIL;
+	}
+	while (!feof(fp)) {
+		// Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT
+		if(fscanf(fp, "%63s %lx %lx %x %hd %hd %hd %lx %hd %hd %hd\n",
+				iface, &dest, &gate, &flags, &ref, &use,
+				&metric, &mask, &mtu, &win, &irtt) != 11) {
+			perror("fscanf()");
+			goto CLOSE_FAIL;
+		}
+		if (flags & RTF_GATEWAY && dest == 0 && mask == 0) {
+			gw_info->count++;
+			SAVE_SET_STRING(gw_info->iface, iface)
+			ina.s_addr = gate;
+			SAVE_SET_STRING(gw_info->ip, inet_ntoa(ina))
+		}
+	}
+	fclose(fp);
+	return;
+CLOSE_FAIL:
+	fclose(fp);
+FAIL:
+	info.gw_info.iface = info.gw_info.ip = strdup("failed");
+	return;
+}
+
 inline void update_net_stats()
 {
 	FILE *net_dev_fp;