From 3e05cdd09405cc6133ebf38ea9ee9afc50fb280f Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 4 Aug 2003 22:45:25 +0000
Subject: Initial checkin

git-svn-id: file:///home/lennart/svn/public/ifmetric/trunk@3 b1ab5a0b-19c4-0310-9d9a-ef184d715f50
---
 src/ifmetric.c | 204 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 204 insertions(+)
 create mode 100644 src/ifmetric.c

(limited to 'src/ifmetric.c')

diff --git a/src/ifmetric.c b/src/ifmetric.c
new file mode 100644
index 0000000..a232061
--- /dev/null
+++ b/src/ifmetric.c
@@ -0,0 +1,204 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <linux/types.h>
+#include <linux/if.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "nlrequest.h"
+#include "getifn.h"
+
+#define MAX_ROUTES 64
+
+struct nlmsghdr* routes[MAX_ROUTES];
+int n_routes = 0;
+
+int enumerate_callback(struct nlmsghdr *n, void *u) {
+    struct rtmsg *r;
+    struct rtattr *a = NULL;
+    int l, *ifn = u;
+
+    if (n->nlmsg_type != RTM_NEWROUTE) {
+        fprintf(stderr, "NETLINK: Got response for wrong request.\n");
+        return -1;
+    }
+
+    r = NLMSG_DATA(n);
+    l = NLMSG_PAYLOAD(n, sizeof(struct rtmsg));
+    a = RTM_RTA(r);
+
+    if (r->rtm_table != RT_TABLE_MAIN)
+        return 0;
+    
+    while(RTA_OK(a, l)) {
+        switch(a->rta_type) {
+            case RTA_OIF:
+
+                if (RTA_PAYLOAD(a) != sizeof(int)) {
+                    fprintf(stderr, "NETLINK: Recieved corrupt RTA_OIF payload.\n");
+                    return -1;
+                }
+                
+                if (*((int*) RTA_DATA(a)) == *ifn) {
+
+                    if (n_routes < MAX_ROUTES) {
+                        struct nlmsghdr* copy;
+
+                        if (!(copy = malloc(n->nlmsg_len))) {
+                            fprintf(stderr, "Could not allocate memory.\n");
+                            return -1;
+                        }
+                            
+                        memcpy(copy, n, n->nlmsg_len);
+                        routes[n_routes++] = copy;
+
+                    } else
+                        fprintf(stderr, "Found too many routes.\n");
+                            
+                    break;
+                }
+
+                
+        }
+        
+        a = RTA_NEXT(a, l);
+    }
+
+    return 0;
+}
+
+int enumerate(int s, int ifn) {
+    struct {
+        struct nlmsghdr n;
+        struct rtmsg r;
+        char a[1024];
+    } req;
+    
+    memset(&req, 0, sizeof(req));
+    req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+    req.n.nlmsg_flags = NLM_F_REQUEST|NLM_F_MATCH;
+    req.n.nlmsg_type = RTM_GETROUTE;
+    
+    req.r.rtm_family = AF_INET;
+    req.r.rtm_table = RT_TABLE_MAIN;
+    
+    return netlink_request(s, (struct nlmsghdr*) &req, enumerate_callback, &ifn);
+}
+
+struct nlmsghdr* set_route_metric(struct nlmsghdr* n, int metric) {
+    struct rtmsg *r;
+    struct rtattr *a = NULL;
+    int l, t;
+
+    r = NLMSG_DATA(n);
+    l = NLMSG_PAYLOAD(n, sizeof(struct rtmsg));
+    a = RTM_RTA(r);
+    
+    while(RTA_OK(a, l)) {
+        switch(a->rta_type) {
+            case RTA_PRIORITY:
+
+                if (RTA_PAYLOAD(a) != sizeof(int)) {
+                    fprintf(stderr, "NETLINK: Recieved corrupt RTA_PRIORITY payload.\n");
+                    return NULL;
+                }
+
+                *((int*) RTA_DATA(a)) = metric;
+                return n;
+        }
+        
+        a = RTA_NEXT(a, l);
+    }
+
+    if ((n = realloc(n, (t = n->nlmsg_len+1024))))
+        addattr32(n, t, RTA_PRIORITY, metric);
+    else
+        fprintf(stderr, "realloc() failed.\n");
+
+    return n;
+}
+
+int delete_route(int s, struct nlmsghdr* n) {
+    assert(s >= 0 && n);
+    
+    n->nlmsg_type = RTM_DELROUTE;
+    n->nlmsg_flags = NLM_F_REQUEST;
+
+    return netlink_request(s, n, NULL, NULL);
+}
+
+int add_route(int s, struct nlmsghdr* n) {
+    assert(s >= 0 && n);
+    
+    n->nlmsg_type = RTM_NEWROUTE;
+    n->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE;
+
+    return netlink_request(s, n, NULL, NULL);
+}
+
+
+int go(char *iface, int metric) {
+    int r = -1, j;
+    int s = -1, ifn;
+
+    if ((s = netlink_open()) < 0)
+        return -1;
+    
+    if ((ifn = getifn(s, iface)) < 0)
+        goto finish;
+
+    n_routes = 0;
+    if (enumerate(s, ifn) < 0)
+        goto finish;
+
+    if (n_routes) {
+        for (j = 0; j < n_routes; j++) {
+             if (delete_route(s, routes[j]) >= 0)
+                 if ((routes[j] = set_route_metric(routes[j], metric)))
+                     add_route(s, routes[j]);
+            
+            free(routes[j]);
+        }
+    }
+    
+    r = 0;
+    
+finish:
+    
+    if (s >= 0)
+        close(s);
+    
+    return r;
+}
+
+int main(int argc, char *argv[]) {
+    char *iface;
+    int metric;
+
+    if (argc <= 1 || (argc > 1 && (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")))) {
+        char *b;
+        
+        if ((b = strrchr(argv[0], '/')))
+            b++;
+        else
+            b = argv[0];
+        
+        printf("Usage: %s <iface> [metric]\n"
+               "\n"
+               "%s is a tool for setting the metrics of all IPv4 routes\n"
+               "attached to a given network interface at once.\n"
+               "\n"
+               "   <iface>    The interface\n"
+               "   <metric>   The new metric (default: 0)\n", b, b);
+        return 0;
+    }
+    
+    iface = argv[1];
+    metric = argc > 2 ? atoi(argv[2]) : 0;
+
+    return go(iface, metric) < 0 ? 1 : 0;
+
+}
-- 
cgit