Initial checkin

git-svn-id: file:///home/lennart/svn/public/ifmetric/trunk@3 b1ab5a0b-19c4-0310-9d9a-ef184d715f50

6 files changed, 470 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..ff501ea
--- /dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,23 @@
+# $Id$
+
+# This file is part of ifmetric.
+#
+# ifmetric is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# ifmetric is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with ifmetric; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+
+
+sbin_PROGRAMS = ifmetric
+
+ifmetric_SOURCES = ifmetric.c getifn.h getifn.c nlrequest.h nlrequest.c
+
diff --git a/src/getifn.c b/src/getifn.c
new file mode 100644
index 0000000..74dfc72
--- /dev/null
+++ b/src/getifn.c
@@ -0,0 +1,77 @@
+#include <string.h>
+#include <stdio.h>
+
+#include "getifn.h"
+#include "nlrequest.h"
+
+struct getifn_info {
+    char ifname[IFNAMSIZ+1];
+    int idx;
+};
+
+int getifn_callback(struct nlmsghdr *n, void *u) {
+    struct rtattr *a = NULL;
+    int l;
+    struct getifn_info *gi = (struct getifn_info*) u;
+    struct ifinfomsg *i;
+
+    if (n->nlmsg_type != RTM_NEWLINK) {
+        fprintf(stderr, "NETLINK: Got response for wrong request.\n");
+        return -1;
+    }
+
+    i = NLMSG_DATA(n);
+    l = NLMSG_PAYLOAD(n, sizeof(struct ifinfomsg));
+    a = IFLA_RTA(i);
+    
+    while(RTA_OK(a, l)) {
+        
+        switch(a->rta_type) {
+            case IFLA_IFNAME:
+                if (strncmp(RTA_DATA(a), gi->ifname, IFNAMSIZ) == 0)  {
+                    gi->idx = i->ifi_index;
+                    return 0;
+                }
+        }
+        a = RTA_NEXT(a, l);
+    }
+    
+    return 0;
+}
+
+int getifn(int s, char *iface) {
+    struct getifn_info gi;
+    
+    struct {
+        struct nlmsghdr n;
+        struct ifinfomsg i;
+        char a[1024];
+    } req;
+    
+    memset(&req, 0, sizeof(req));
+    req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+    req.n.nlmsg_flags = NLM_F_REQUEST|NLM_F_MATCH;
+    req.n.nlmsg_type = RTM_GETLINK;
+    
+    req.i.ifi_family = AF_UNSPEC;
+    req.i.ifi_change = -1;
+
+    memset(&gi, 0, sizeof(gi));
+    strncpy(gi.ifname, iface, IFNAMSIZ);
+    gi.idx = -1;
+
+    if (addattr_l(&req.n, sizeof(req), IFLA_IFNAME, gi.ifname, IFNAMSIZ+1) < 0) {
+        fprintf(stderr, "Failed to add attribute to netlink message\n");
+        return -1;
+    }
+    
+    if (netlink_request(s, (struct nlmsghdr*) &req, getifn_callback, &gi) < 0)
+        return -1;
+
+    if (gi.idx < 0) {
+        fprintf(stderr, "Interface '%s' not existent.\n", iface);
+        return -1;
+    }
+    
+    return gi.idx;
+}
diff --git a/src/getifn.h b/src/getifn.h
new file mode 100644
index 0000000..3c4cff8
--- /dev/null
+++ b/src/getifn.h
@@ -0,0 +1,7 @@
+#ifndef foogetifnhfoo
+#define foogetifnhfoo
+
+/* Return the kernel index for the given interface. */
+int getifn(int s, char *iface);
+
+#endif
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;
+
+}
diff --git a/src/nlrequest.c b/src/nlrequest.c
new file mode 100644
index 0000000..1f72357
--- /dev/null
+++ b/src/nlrequest.c
@@ -0,0 +1,139 @@
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "nlrequest.h"
+
+int netlink_open(void) {
+    struct sockaddr_nl addr;
+    int s;
+    
+    if ((s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0) {
+        fprintf(stderr, "socket(PF_NETLINK): %s\n", strerror(errno));
+        return -1;
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.nl_family = AF_NETLINK;
+    addr.nl_groups = 0;
+    addr.nl_pid = getpid();
+
+    if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+        fprintf(stderr, "bind(): %s\n", strerror(errno));
+        return -1;
+    }
+
+    return s;
+}
+
+
+int netlink_request(int s, struct nlmsghdr *n, int (*callback) (struct nlmsghdr *n, void *u), void *u) {
+    static int seq = 0;
+    pid_t pid = getpid();
+    assert(s >= 0 && n);
+
+    n->nlmsg_seq = seq++;
+    n->nlmsg_flags |= NLM_F_ACK;
+    
+    if (send(s, n, n->nlmsg_len, 0) < 0) {
+        fprintf(stderr, "NETLINK: send(): %s\n", strerror(errno));
+        return -1;
+    }
+
+    for (;;) {
+        int bytes;
+        char replybuf[1024];
+        struct nlmsghdr *p = (struct nlmsghdr *) replybuf;
+        
+        if ((bytes = recv(s, &replybuf, sizeof(replybuf), 0)) < 0) {
+            fprintf(stderr, "recv(): %s\n", strerror(errno));
+            return -1;
+        }
+
+        for (; bytes > 0; p = NLMSG_NEXT(p, bytes)) {
+            int ret;
+            
+             if (!NLMSG_OK(p, bytes) || bytes < sizeof(struct nlmsghdr) || bytes < p->nlmsg_len) {
+                fprintf(stderr, "NETLINK: Packet too small or truncated!\n");
+                return -1;
+            }
+
+            if (p->nlmsg_type == NLMSG_DONE)
+                return 0;
+
+            if (p->nlmsg_type == NLMSG_ERROR) {
+                struct nlmsgerr *e = (struct nlmsgerr *) NLMSG_DATA (p);
+
+                if (e->error) {
+                    fprintf(stderr, "NETLINK: Error: %s\n", strerror(-e->error));
+                    return -1;
+                } else
+                    return 0;
+            }
+
+            if (p->nlmsg_pid != pid)
+                continue;
+
+            if (p->nlmsg_seq != n->nlmsg_seq) {
+                fprintf(stderr, "NETLINK: Received message with bogus sequence number!\n");
+                continue;
+            }
+
+            if (callback)
+                if ((ret = callback(p, u)) < 0)
+                    return ret;
+        }
+    }
+        
+    return 0;
+}
+
+/*
+ * Utility function comes from iproute2.
+ * Author: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) {
+    int len;
+    struct rtattr *rta; 
+    
+    len = RTA_LENGTH(alen);
+    
+    if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
+        return -1;
+    
+    rta = (struct rtattr*) (((char*)n) + NLMSG_ALIGN (n->nlmsg_len));
+    rta->rta_type = type;
+    rta->rta_len = len;
+    memcpy (RTA_DATA(rta), data, alen);
+    n->nlmsg_len = NLMSG_ALIGN (n->nlmsg_len) + len;
+    
+    return 0;
+}
+
+/*
+ * Utility function comes from iproute2.
+ * Author: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+
+int addattr32(struct nlmsghdr *n, int maxlen, int type, int data) {
+    int len;
+    struct rtattr *rta;
+    
+    len = RTA_LENGTH(4);
+    
+    if (NLMSG_ALIGN (n->nlmsg_len) + len > maxlen)
+        return -1;
+    
+    rta = (struct rtattr*) (((char*)n) + NLMSG_ALIGN (n->nlmsg_len));
+    rta->rta_type = type;
+    rta->rta_len = len;
+    memcpy (RTA_DATA(rta), &data, 4);
+    n->nlmsg_len = NLMSG_ALIGN (n->nlmsg_len) + len;
+    
+    return 0;
+}
+
diff --git a/src/nlrequest.h b/src/nlrequest.h
new file mode 100644
index 0000000..efe3450
--- /dev/null
+++ b/src/nlrequest.h
@@ -0,0 +1,20 @@
+#ifndef foonlrequesthfoo
+#define foonlrequesthfoo
+
+#include <sys/socket.h>
+#include <linux/types.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+
+/* Issue a netlink message and wait for a response, calling 'callback' for every response message */
+int netlink_request(int s, struct nlmsghdr *n, int (*callback) (struct nlmsghdr *n, void*u), void *u);
+
+int addattr32(struct nlmsghdr *n, int maxlen, int type, int data);
+int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen);
+
+int netlink_open(void);
+    
+
+#endif
+