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-rw-r--r--loopback-setup.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/loopback-setup.c b/loopback-setup.c
new file mode 100644
index 0000000000..e37bf4190b
--- /dev/null
+++ b/loopback-setup.c
@@ -0,0 +1,276 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd 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.
+
+ systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <asm/types.h>
+#include <netinet/in.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include "util.h"
+#include "macro.h"
+#include "loopback-setup.h"
+
+enum {
+ REQUEST_NONE = 0,
+ REQUEST_ADDRESS_IPV4 = 1,
+ REQUEST_ADDRESS_IPV6 = 2,
+ REQUEST_FLAGS = 4,
+ REQUEST_ALL = 7
+};
+
+#define NLMSG_TAIL(nmsg) \
+ ((struct rtattr *) (((uint8_t*) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
+
+static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type, const void *data, size_t data_length) {
+ size_t length;
+ struct rtattr *rta;
+
+ length = RTA_LENGTH(data_length);
+
+ if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
+ return -E2BIG;
+
+ rta = NLMSG_TAIL(n);
+ rta->rta_type = type;
+ rta->rta_len = length;
+ memcpy(RTA_DATA(rta), data, data_length);
+ n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
+
+ return 0;
+}
+
+static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, const struct sockaddr *sa, socklen_t sa_len) {
+
+ for (;;) {
+ ssize_t l;
+
+ if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
+ return l;
+
+ if (errno != EINTR)
+ return -errno;
+ }
+}
+
+static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struct sockaddr *sa, socklen_t *sa_len) {
+
+ for (;;) {
+ ssize_t l;
+
+ if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
+ return l;
+
+ if (errno != EINTR)
+ return -errno;
+ }
+}
+
+static int add_adresses(int fd, int if_loopback) {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_nl nl;
+ } sa;
+ union {
+ struct nlmsghdr header;
+ uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
+ NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
+ RTA_LENGTH(sizeof(struct in6_addr))];
+ } request;
+
+ struct ifaddrmsg *ifaddrmsg;
+ uint32_t ipv4_address = htonl(INADDR_LOOPBACK);
+ int r;
+
+ zero(request);
+
+ request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+ request.header.nlmsg_type = RTM_NEWADDR;
+ request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK;
+ request.header.nlmsg_seq = REQUEST_ADDRESS_IPV4;
+
+ ifaddrmsg = NLMSG_DATA(&request.header);
+ ifaddrmsg->ifa_family = AF_INET;
+ ifaddrmsg->ifa_prefixlen = 8;
+ ifaddrmsg->ifa_flags = IFA_F_PERMANENT;
+ ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
+ ifaddrmsg->ifa_index = if_loopback;
+
+ if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
+ return r;
+
+ zero(sa);
+ sa.nl.nl_family = AF_NETLINK;
+
+ if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
+ return -errno;
+
+ request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+ request.header.nlmsg_seq = REQUEST_ADDRESS_IPV6;
+
+ ifaddrmsg->ifa_family = AF_INET6;
+ ifaddrmsg->ifa_prefixlen = 128;
+
+ if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
+ return r;
+
+ if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
+ return -errno;
+
+ return 0;
+}
+
+static int start_interface(int fd, int if_loopback) {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_nl nl;
+ } sa;
+ union {
+ struct nlmsghdr header;
+ uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
+ NLMSG_ALIGN(sizeof(struct ifinfomsg))];
+ } request;
+
+ struct ifinfomsg *ifinfomsg;
+
+ zero(request);
+
+ request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+ request.header.nlmsg_type = RTM_NEWLINK;
+ request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
+ request.header.nlmsg_seq = REQUEST_FLAGS;
+
+ ifinfomsg = NLMSG_DATA(&request.header);
+ ifinfomsg->ifi_family = AF_UNSPEC;
+ ifinfomsg->ifi_index = if_loopback;
+ ifinfomsg->ifi_flags = IFF_UP;
+ ifinfomsg->ifi_change = IFF_UP;
+
+ zero(sa);
+ sa.nl.nl_family = AF_NETLINK;
+
+ if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
+ return -errno;
+
+ return 0;
+}
+
+static int read_response(int fd) {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_nl nl;
+ } sa;
+ union {
+ struct nlmsghdr header;
+ uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
+ NLMSG_ALIGN(sizeof(struct nlmsgerr))];
+ } response;
+
+ ssize_t l;
+ socklen_t sa_len = sizeof(sa);
+ struct nlmsgerr *nlmsgerr;
+
+ if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
+ return -errno;
+
+ if (sa_len != sizeof(sa.nl) ||
+ sa.nl.nl_family != AF_NETLINK)
+ return -EIO;
+
+ if (sa.nl.nl_pid != 0)
+ return 0;
+
+ if ((size_t) l < sizeof(struct nlmsghdr))
+ return -EIO;
+
+ if (response.header.nlmsg_type != NLMSG_ERROR ||
+ (pid_t) response.header.nlmsg_pid != getpid() ||
+ response.header.nlmsg_seq >= REQUEST_ALL)
+ return 0;
+
+ if ((size_t) l < NLMSG_LENGTH(sizeof(struct nlmsgerr)) ||
+ response.header.nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
+ return -EIO;
+
+ nlmsgerr = NLMSG_DATA(&response.header);
+
+ if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST)
+ return nlmsgerr->error;
+
+ return response.header.nlmsg_seq;
+}
+
+int loopback_setup(void) {
+ int r, if_loopback;
+ union {
+ struct sockaddr sa;
+ struct sockaddr_nl nl;
+ struct sockaddr_storage storage;
+ } sa;
+ int requests = REQUEST_NONE;
+
+ int fd;
+
+ errno = 0;
+ if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
+ return errno ? -errno : -ENODEV;
+
+ if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
+ return -errno;
+
+ zero(sa);
+ sa.nl.nl_family = AF_NETLINK;
+
+ if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
+ r = -errno;
+ goto finish;
+ }
+
+ if ((r = add_adresses(fd, if_loopback)) < 0)
+ goto finish;
+
+ if ((r = start_interface(fd, if_loopback)) < 0)
+ goto finish;
+
+ do {
+ if ((r = read_response(fd)) < 0)
+ goto finish;
+
+ requests |= r;
+
+ } while (requests != REQUEST_ALL);
+
+ r = 0;
+
+finish:
+ if (r < 0)
+ log_error("Failed to configure loopback device: %s", strerror(-r));
+
+ if (fd >= 0)
+ close_nointr_nofail(fd);
+
+ return r;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-26 23:27:01 +0000