diff options
Diffstat (limited to 'src/ifmetric.c')
| -rw-r--r-- | src/ifmetric.c | 204 |
1 files changed, 204 insertions, 0 deletions
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; + +} |