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-rw-r--r--ip/ipvrf.c654
1 files changed, 654 insertions, 0 deletions
diff --git a/ip/ipvrf.c b/ip/ipvrf.c
new file mode 100644
index 0000000..e7c702a
--- /dev/null
+++ b/ip/ipvrf.c
@@ -0,0 +1,654 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * ipvrf.c "ip vrf"
+ *
+ * Authors: David Ahern <dsa@cumulusnetworks.com>
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/mount.h>
+#include <linux/bpf.h>
+#include <linux/if.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <dirent.h>
+#include <errno.h>
+#include <limits.h>
+
+#include "rt_names.h"
+#include "utils.h"
+#include "ip_common.h"
+#include "bpf_util.h"
+#include "selinux.h"
+
+#define CGRP_PROC_FILE "/cgroup.procs"
+
+static struct link_filter vrf_filter;
+
+static void usage(void)
+{
+ fprintf(stderr,
+ "Usage: ip vrf show [NAME] ...\n"
+ " ip vrf exec [NAME] cmd ...\n"
+ " ip vrf identify [PID]\n"
+ " ip vrf pids [NAME]\n");
+
+ exit(-1);
+}
+
+/*
+ * parse process based cgroup file looking for PATH/vrf/NAME where
+ * NAME is the name of the vrf the process is associated with
+ */
+static int vrf_identify(pid_t pid, char *name, size_t len)
+{
+ char path[PATH_MAX];
+ char buf[4096];
+ char *vrf, *end;
+ FILE *fp;
+
+ snprintf(path, sizeof(path), "/proc/%d/cgroup", pid);
+ fp = fopen(path, "r");
+ if (!fp)
+ return -1;
+
+ memset(name, 0, len);
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ /* want the controller-less cgroup */
+ if (strstr(buf, "::/") == NULL)
+ continue;
+
+ vrf = strstr(buf, "/vrf/");
+ if (vrf) {
+ vrf += 5; /* skip past "/vrf/" */
+ end = strchr(vrf, '\n');
+ if (end)
+ *end = '\0';
+
+ strlcpy(name, vrf, len);
+ break;
+ }
+ }
+
+ fclose(fp);
+
+ return 0;
+}
+
+static int ipvrf_identify(int argc, char **argv)
+{
+ char vrf[32];
+ int rc;
+ unsigned int pid;
+
+ if (argc < 1)
+ pid = getpid();
+ else if (argc > 1)
+ invarg("Extra arguments specified\n", argv[1]);
+ else if (get_unsigned(&pid, argv[0], 10))
+ invarg("Invalid pid\n", argv[0]);
+
+ rc = vrf_identify(pid, vrf, sizeof(vrf));
+ if (!rc) {
+ if (vrf[0] != '\0')
+ printf("%s\n", vrf);
+ } else {
+ fprintf(stderr, "Failed to lookup vrf association: %s\n",
+ strerror(errno));
+ }
+
+ return rc;
+}
+
+/* read PATH/vrf/NAME/cgroup.procs file */
+static void read_cgroup_pids(const char *base_path, char *name)
+{
+ char path[PATH_MAX];
+ char buf[4096];
+ FILE *fp;
+
+ if (snprintf(path, sizeof(path), "%s/vrf/%s%s",
+ base_path, name, CGRP_PROC_FILE) >= sizeof(path))
+ return;
+
+ fp = fopen(path, "r");
+ if (!fp)
+ return; /* no cgroup file, nothing to show */
+
+ /* dump contents (pids) of cgroup.procs */
+ while (fgets(buf, sizeof(buf), fp)) {
+ char *nl, comm[32];
+
+ nl = strchr(buf, '\n');
+ if (nl)
+ *nl = '\0';
+
+ if (get_command_name(buf, comm, sizeof(comm)))
+ strcpy(comm, "<terminated?>");
+
+ printf("%5s %s\n", buf, comm);
+ }
+
+ fclose(fp);
+}
+
+/* recurse path looking for PATH[/NETNS]/vrf/NAME */
+static int recurse_dir(char *base_path, char *name, const char *netns)
+{
+ char path[PATH_MAX];
+ struct dirent *de;
+ struct stat fstat;
+ int rc;
+ DIR *d;
+
+ d = opendir(base_path);
+ if (!d)
+ return -1;
+
+ while ((de = readdir(d)) != NULL) {
+ if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
+ continue;
+
+ if (!strcmp(de->d_name, "vrf")) {
+ const char *pdir = strrchr(base_path, '/');
+
+ /* found a 'vrf' directory. if it is for the given
+ * namespace then dump the cgroup pids
+ */
+ if (*netns == '\0' ||
+ (pdir && !strcmp(pdir+1, netns)))
+ read_cgroup_pids(base_path, name);
+
+ continue;
+ }
+
+ /* is this a subdir that needs to be walked */
+ if (snprintf(path, sizeof(path), "%s/%s",
+ base_path, de->d_name) >= sizeof(path))
+ continue;
+
+ if (lstat(path, &fstat) < 0)
+ continue;
+
+ if (S_ISDIR(fstat.st_mode)) {
+ rc = recurse_dir(path, name, netns);
+ if (rc != 0)
+ goto out;
+ }
+ }
+
+ rc = 0;
+out:
+ closedir(d);
+
+ return rc;
+}
+
+static int ipvrf_get_netns(char *netns, int len)
+{
+ if (netns_identify_pid("self", netns, len-3)) {
+ fprintf(stderr, "Failed to get name of network namespace: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ if (*netns != '\0')
+ strcat(netns, "-ns");
+
+ return 0;
+}
+
+static int ipvrf_pids(int argc, char **argv)
+{
+ char *mnt, *vrf;
+ char netns[256];
+ int ret = -1;
+
+ if (argc != 1) {
+ fprintf(stderr, "Invalid arguments\n");
+ return -1;
+ }
+
+ vrf = argv[0];
+ if (!name_is_vrf(vrf)) {
+ fprintf(stderr, "Invalid VRF name\n");
+ return -1;
+ }
+
+ mnt = find_cgroup2_mount(true);
+ if (!mnt)
+ return -1;
+
+ if (ipvrf_get_netns(netns, sizeof(netns)) < 0)
+ goto out;
+
+ ret = recurse_dir(mnt, vrf, netns);
+
+out:
+ free(mnt);
+
+ return ret;
+}
+
+/* load BPF program to set sk_bound_dev_if for sockets */
+static char bpf_log_buf[256*1024];
+
+static int prog_load(int idx)
+{
+ struct bpf_insn prog[] = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_3, idx),
+ BPF_MOV64_IMM(BPF_REG_2,
+ offsetof(struct bpf_sock, bound_dev_if)),
+ BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_3,
+ offsetof(struct bpf_sock, bound_dev_if)),
+ BPF_MOV64_IMM(BPF_REG_0, 1), /* r0 = verdict */
+ BPF_EXIT_INSN(),
+ };
+
+ return bpf_program_load(BPF_PROG_TYPE_CGROUP_SOCK, prog, sizeof(prog),
+ "GPL", bpf_log_buf, sizeof(bpf_log_buf),
+ false);
+}
+
+static int vrf_configure_cgroup(const char *path, int ifindex)
+{
+ int rc = -1, cg_fd, prog_fd = -1;
+
+ cg_fd = open(path, O_DIRECTORY | O_RDONLY);
+ if (cg_fd < 0) {
+ fprintf(stderr,
+ "Failed to open cgroup path: '%s'\n",
+ strerror(errno));
+ goto out;
+ }
+
+ /*
+ * Load bpf program into kernel and attach to cgroup to affect
+ * socket creates
+ */
+ prog_fd = prog_load(ifindex);
+ if (prog_fd < 0) {
+ fprintf(stderr, "Failed to load BPF prog: '%s'\n%s",
+ strerror(errno), bpf_log_buf);
+
+ if (errno != EPERM) {
+ fprintf(stderr,
+ "Kernel compiled with CGROUP_BPF enabled?\n");
+ }
+ goto out;
+ }
+
+ if (bpf_program_attach(prog_fd, cg_fd, BPF_CGROUP_INET_SOCK_CREATE)) {
+ fprintf(stderr, "Failed to attach prog to cgroup: '%s'\n",
+ strerror(errno));
+ goto out;
+ }
+
+ rc = 0;
+out:
+ close(cg_fd);
+ close(prog_fd);
+
+ return rc;
+}
+
+/* get base path for controller-less cgroup for a process.
+ * path returned does not include /vrf/NAME if it exists
+ */
+static int vrf_path(char *vpath, size_t len)
+{
+ char path[PATH_MAX];
+ char buf[4096];
+ char *vrf;
+ FILE *fp;
+
+ snprintf(path, sizeof(path), "/proc/%d/cgroup", getpid());
+ fp = fopen(path, "r");
+ if (!fp)
+ return -1;
+
+ vpath[0] = '\0';
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ char *start, *nl;
+
+ start = strstr(buf, "::/");
+ if (!start)
+ continue;
+
+ /* advance past '::' */
+ start += 2;
+
+ nl = strchr(start, '\n');
+ if (nl)
+ *nl = '\0';
+
+ vrf = strstr(start, "/vrf");
+ if (vrf)
+ *vrf = '\0';
+
+ strlcpy(vpath, start, len);
+
+ /* if vrf path is just / then return nothing */
+ if (!strcmp(vpath, "/"))
+ vpath[0] = '\0';
+
+ break;
+ }
+
+ fclose(fp);
+
+ return 0;
+}
+
+static int vrf_switch(const char *name)
+{
+ char path[PATH_MAX], *mnt, pid[16];
+ char vpath[PATH_MAX], netns[256];
+ int ifindex = 0;
+ int rc = -1, len, fd = -1;
+
+ if (strcmp(name, "default")) {
+ ifindex = name_is_vrf(name);
+ if (!ifindex) {
+ fprintf(stderr, "Invalid VRF name\n");
+ return -1;
+ }
+ }
+
+ mnt = find_cgroup2_mount(true);
+ if (!mnt)
+ return -1;
+
+ /* -1 on length to add '/' to the end */
+ if (ipvrf_get_netns(netns, sizeof(netns) - 1) < 0)
+ goto out;
+
+ if (vrf_path(vpath, sizeof(vpath)) < 0) {
+ fprintf(stderr, "Failed to get base cgroup path: %s\n",
+ strerror(errno));
+ goto out;
+ }
+
+ /* if path already ends in netns then don't add it again */
+ if (*netns != '\0') {
+ char *pdir = strrchr(vpath, '/');
+
+ if (!pdir)
+ pdir = vpath;
+ else
+ pdir++;
+
+ if (strcmp(pdir, netns) == 0)
+ *pdir = '\0';
+
+ strcat(netns, "/");
+ }
+
+ /* path to cgroup; make sure buffer has room to cat "/cgroup.procs"
+ * to the end of the path
+ */
+ len = snprintf(path, sizeof(path) - sizeof(CGRP_PROC_FILE),
+ "%s%s/%svrf/%s",
+ mnt, vpath, netns, ifindex ? name : "");
+ if (len > sizeof(path) - sizeof(CGRP_PROC_FILE)) {
+ fprintf(stderr, "Invalid path to cgroup2 mount\n");
+ goto out;
+ }
+
+ if (make_path(path, 0755)) {
+ fprintf(stderr, "Failed to setup vrf cgroup2 directory\n");
+ goto out;
+ }
+
+ if (ifindex && vrf_configure_cgroup(path, ifindex))
+ goto out;
+
+ /*
+ * write pid to cgroup.procs making process part of cgroup
+ */
+ strcat(path, CGRP_PROC_FILE);
+ fd = open(path, O_RDWR | O_APPEND);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to open cgroups.procs file: %s.\n",
+ strerror(errno));
+ goto out;
+ }
+
+ snprintf(pid, sizeof(pid), "%d", getpid());
+ if (write(fd, pid, strlen(pid)) < 0) {
+ fprintf(stderr, "Failed to join cgroup\n");
+ goto out2;
+ }
+
+ rc = 0;
+out2:
+ close(fd);
+out:
+ free(mnt);
+
+ drop_cap();
+
+ return rc;
+}
+
+static int do_switch(void *arg)
+{
+ char *vrf = arg;
+
+ return vrf_switch(vrf);
+}
+
+static int ipvrf_exec(int argc, char **argv)
+{
+ if (argc < 1) {
+ fprintf(stderr, "No VRF name specified\n");
+ return -1;
+ }
+ if (argc < 2) {
+ fprintf(stderr, "No command specified\n");
+ return -1;
+ }
+
+ if (is_selinux_enabled() && setexecfilecon(argv[1], "ifconfig_t")) {
+ fprintf(stderr, "setexecfilecon for \"%s\" failed\n", argv[1]);
+ return -1;
+ }
+
+ return -cmd_exec(argv[1], argv + 1, !!batch_mode, do_switch, argv[0]);
+}
+
+/* reset VRF association of current process to default VRF;
+ * used by netns_exec
+ */
+void vrf_reset(void)
+{
+ char vrf[32];
+
+ if (vrf_identify(getpid(), vrf, sizeof(vrf)) ||
+ (vrf[0] == '\0'))
+ return;
+
+ vrf_switch("default");
+}
+
+static int ipvrf_filter_req(struct nlmsghdr *nlh, int reqlen)
+{
+ struct rtattr *linkinfo;
+ int err;
+
+ if (vrf_filter.kind) {
+ linkinfo = addattr_nest(nlh, reqlen, IFLA_LINKINFO);
+
+ err = addattr_l(nlh, reqlen, IFLA_INFO_KIND, vrf_filter.kind,
+ strlen(vrf_filter.kind));
+ if (err)
+ return err;
+
+ addattr_nest_end(nlh, linkinfo);
+ }
+
+ return 0;
+}
+
+/* input arg is linkinfo */
+static __u32 vrf_table_linkinfo(struct rtattr *li[])
+{
+ struct rtattr *attr[IFLA_VRF_MAX + 1];
+
+ if (li[IFLA_INFO_DATA]) {
+ parse_rtattr_nested(attr, IFLA_VRF_MAX, li[IFLA_INFO_DATA]);
+
+ if (attr[IFLA_VRF_TABLE])
+ return rta_getattr_u32(attr[IFLA_VRF_TABLE]);
+ }
+
+ return 0;
+}
+
+static int ipvrf_print(struct nlmsghdr *n)
+{
+ struct ifinfomsg *ifi = NLMSG_DATA(n);
+ struct rtattr *tb[IFLA_MAX+1];
+ struct rtattr *li[IFLA_INFO_MAX+1];
+ int len = n->nlmsg_len;
+ const char *name;
+ __u32 tb_id;
+
+ len -= NLMSG_LENGTH(sizeof(*ifi));
+ if (len < 0)
+ return 0;
+
+ if (vrf_filter.ifindex && vrf_filter.ifindex != ifi->ifi_index)
+ return 0;
+
+ parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
+
+ /* kernel does not support filter by master device */
+ if (tb[IFLA_MASTER]) {
+ int master = *(int *)RTA_DATA(tb[IFLA_MASTER]);
+
+ if (vrf_filter.master && master != vrf_filter.master)
+ return 0;
+ }
+
+ if (!tb[IFLA_IFNAME]) {
+ fprintf(stderr,
+ "BUG: device with ifindex %d has nil ifname\n",
+ ifi->ifi_index);
+ return 0;
+ }
+ name = rta_getattr_str(tb[IFLA_IFNAME]);
+
+ /* missing LINKINFO means not VRF. e.g., kernel does not
+ * support filtering on kind, so userspace needs to handle
+ */
+ if (!tb[IFLA_LINKINFO])
+ return 0;
+
+ parse_rtattr_nested(li, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
+
+ if (!li[IFLA_INFO_KIND])
+ return 0;
+
+ if (strcmp(RTA_DATA(li[IFLA_INFO_KIND]), "vrf"))
+ return 0;
+
+ tb_id = vrf_table_linkinfo(li);
+ if (!tb_id) {
+ fprintf(stderr,
+ "BUG: VRF %s is missing table id\n", name);
+ return 0;
+ }
+
+ open_json_object(NULL);
+ print_string(PRINT_ANY, "name", "%-16s", name);
+ print_uint(PRINT_ANY, "table", " %5u", tb_id);
+ print_string(PRINT_FP, NULL, "%s", "\n");
+ close_json_object();
+
+ return 1;
+}
+
+static int ipvrf_show(int argc, char **argv)
+{
+ struct nlmsg_chain linfo = { NULL, NULL};
+ int rc = 0;
+
+ vrf_filter.kind = "vrf";
+
+ if (argc > 1)
+ usage();
+
+ if (argc == 1) {
+ __u32 tb_id;
+
+ tb_id = ipvrf_get_table(argv[0]);
+ if (!tb_id) {
+ fprintf(stderr, "Invalid VRF\n");
+ return 1;
+ }
+ printf("%s %u\n", argv[0], tb_id);
+ return 0;
+ }
+
+ if (ip_link_list(ipvrf_filter_req, &linfo) == 0) {
+ struct nlmsg_list *l;
+ unsigned nvrf = 0;
+
+ new_json_obj(json);
+
+ print_string(PRINT_FP, NULL, "%-16s", "Name");
+ print_string(PRINT_FP, NULL, " %5s\n", "Table");
+ print_string(PRINT_FP, NULL, "%s\n",
+ "-----------------------");
+
+ for (l = linfo.head; l; l = l->next)
+ nvrf += ipvrf_print(&l->h);
+
+ if (!nvrf)
+ print_string(PRINT_FP, NULL, "%s\n",
+ "No VRF has been configured");
+ delete_json_obj();
+ } else
+ rc = 1;
+
+ free_nlmsg_chain(&linfo);
+
+ return rc;
+}
+
+int do_ipvrf(int argc, char **argv)
+{
+ if (argc == 0)
+ return ipvrf_show(0, NULL);
+
+ if (matches(*argv, "identify") == 0)
+ return ipvrf_identify(argc-1, argv+1);
+
+ if (matches(*argv, "pids") == 0)
+ return ipvrf_pids(argc-1, argv+1);
+
+ if (matches(*argv, "exec") == 0)
+ return ipvrf_exec(argc-1, argv+1);
+
+ if (matches(*argv, "show") == 0 ||
+ matches(*argv, "lst") == 0 ||
+ matches(*argv, "list") == 0)
+ return ipvrf_show(argc-1, argv+1);
+
+ if (matches(*argv, "help") == 0)
+ usage();
+
+ fprintf(stderr, "Command \"%s\" is unknown, try \"ip vrf help\".\n",
+ *argv);
+
+ exit(-1);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-09 02:03:38 +0000