loopback: configure lo device on bootup

.gitignore

@@ -1,5 +1,6 @@
 *~
 test-ns
+test-loopback
 systemd-initctl.service
 systemd-logger.service
 systemd-cgroups-agent

Makefile.am

@@ -53,7 +53,8 @@ pkglibexec_PROGRAMS = \
 noinst_PROGRAMS = \
 	test-engine \
 	test-job-type \
-	test-ns
+	test-ns \
+	test-loopback
 
 dbuspolicy_DATA = \
 	org.freedesktop.systemd1.conf
@@ -155,6 +156,8 @@ COMMON_SOURCES = \
 	mount-setup.h \
 	hostname-setup.c \
 	hostname-setup.h \
+	loopback-setup.c \
+	loopback-setup.h \
 	utmp-wtmp.c \
 	utmp-wtmp.h \
 	specifier.c \
@@ -203,6 +206,14 @@ test_ns_SOURCES = \
 test_ns_CPPFLAGS = $(systemd_CPPFLAGS)
 test_ns_LDADD = $(systemd_LDADD)
 
+test_loopback_SOURCES = \
+	$(BASIC_SOURCES) \
+	test-loopback.c \
+	loopback-setup.c
+
+test_loopback_CPPFLAGS = $(systemd_CPPFLAGS)
+test_loopback_LDADD = $(systemd_LDADD)
+
 systemd_logger_SOURCES = \
 	$(BASIC_SOURCES) \
 	logger.c

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;
+}

loopback-setup.h

@@ -0,0 +1,27 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#ifndef fooloopbacksetuphfoo
+#define fooloopbacksetuphfoo
+
+/***
+  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/>.
+***/
+
+int loopback_setup(void);
+
+#endif

main.c

@@ -36,6 +36,7 @@
 #include "log.h"
 #include "mount-setup.h"
 #include "hostname-setup.h"
+#include "loopback-setup.h"
 #include "load-fragment.h"
 #include "fdset.h"
 
@@ -641,8 +642,10 @@ int main(int argc, char *argv[]) {
 
         log_debug("systemd running in %s mode.", manager_running_as_to_string(running_as));
 
-        if (running_as == MANAGER_INIT)
+        if (running_as == MANAGER_INIT) {
                 hostname_setup();
+                loopback_setup();
+        }
 
         if ((r = manager_new(running_as, confirm_spawn, &m)) < 0) {
                 log_error("Failed to allocate manager object: %s", strerror(-r));

test-loopback.c

@@ -0,0 +1,35 @@
+/*-*- 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 <string.h>
+#include <stdio.h>
+
+#include "loopback-setup.h"
+
+int main(int argc, char* argv[]) {
+        int r;
+
+        if ((r = loopback_setup()) < 0)
+                fprintf(stderr, "loopback: %s\n", strerror(-r));
+
+        return 0;
+}