diff options
| -rw-r--r-- | Makefile.am | 2 | ||||
| -rw-r--r-- | build-root.c | 182 | ||||
| -rw-r--r-- | network.c | 200 | ||||
| -rw-r--r-- | network.h | 24 |
4 files changed, 227 insertions, 181 deletions
diff --git a/Makefile.am b/Makefile.am index 71a9d6a..dbe0c1a 100644 --- a/Makefile.am +++ b/Makefile.am @@ -8,6 +8,8 @@ bin_PROGRAMS = build-root build_root_SOURCES = \ build-root.c \ + network.h \ + network.c \ utils.h \ utils.c \ $(NULL) diff --git a/build-root.c b/build-root.c index 15d763b..ef3cdda 100644 --- a/build-root.c +++ b/build-root.c @@ -18,18 +18,8 @@ #include "config.h" -#include <arpa/inet.h> -#include <getopt.h> -#include <grp.h> -#include <linux/loop.h> -#include <linux/netlink.h> -#include <linux/rtnetlink.h> -#include <net/if.h> -#include <netinet/in.h> #include <poll.h> -#include <pwd.h> #include <sched.h> -#include <signal.h> #include <sys/mount.h> #include <sys/socket.h> #include <sys/wait.h> @@ -37,9 +27,9 @@ #include <sys/signalfd.h> #include <sys/capability.h> #include <sys/prctl.h> -#include <sys/utsname.h> #include "utils.h" +#include "network.h" /* Globals to avoid having to use getuid(), since the uid/gid changes during runtime */ static uid_t uid; @@ -556,176 +546,6 @@ create_file (const char *path, return res; } -static void * -add_rta (struct nlmsghdr *header, - int type, - size_t size) -{ - struct rtattr *rta; - size_t rta_size = RTA_LENGTH(size); - - rta = (struct rtattr*)((char *)header + NLMSG_ALIGN(header->nlmsg_len)); - rta->rta_type = type; - rta->rta_len = rta_size; - - header->nlmsg_len = NLMSG_ALIGN(header->nlmsg_len) + rta_size; - - return RTA_DATA(rta); -} - -static int -rtnl_send_request (int rtnl_fd, - struct nlmsghdr *header) -{ - struct sockaddr_nl dst_addr = { AF_NETLINK, 0 }; - ssize_t sent; - - sent = sendto (rtnl_fd, (void *)header, header->nlmsg_len, 0, - (struct sockaddr *)&dst_addr, sizeof (dst_addr)); - if (sent < 0) - return 1; - - return 0; -} - -static int -rtnl_read_reply (int rtnl_fd, - int seq_nr) -{ - char buffer[1024]; - ssize_t received; - struct nlmsghdr *rheader; - - while (1) - { - received = recv (rtnl_fd, buffer, sizeof(buffer), 0); - if (received < 0) - return 1; - - rheader = (struct nlmsghdr *)buffer; - while (received >= NLMSG_HDRLEN) - { - if (rheader->nlmsg_seq != seq_nr) - return 1; - if (rheader->nlmsg_pid != getpid ()) - return 1; - if (rheader->nlmsg_type == NLMSG_ERROR) - { - uint32_t *err = NLMSG_DATA(rheader); - if (*err == 0) - return 0; - - return 1; - } - if (rheader->nlmsg_type == NLMSG_DONE) - return 0; - - rheader = NLMSG_NEXT(rheader, received); - } - } -} - -static int -rtnl_do_request (int rtnl_fd, - struct nlmsghdr *header) -{ - if (!rtnl_send_request (rtnl_fd, header)) - return 1; - - if (!rtnl_read_reply (rtnl_fd, header->nlmsg_seq)) - return 1; - - return 0; -} - -static struct nlmsghdr * -rtnl_setup_request (char *buffer, - int type, - int flags, - size_t size) -{ - struct nlmsghdr *header; - size_t len = NLMSG_LENGTH (size); - static uint32_t counter = 0; - - memset (buffer, 0, len); - - header = (struct nlmsghdr *)buffer; - header->nlmsg_len = len; - header->nlmsg_type = type; - header->nlmsg_flags = flags | NLM_F_REQUEST; - header->nlmsg_seq = counter++; - header->nlmsg_pid = getpid (); - - return (struct nlmsghdr *)header; -} - -static int -loopback_setup (void) -{ - int r, if_loopback; - cleanup_fd int rtnl_fd = -1; - char buffer[1024]; - struct sockaddr_nl src_addr = { AF_NETLINK, 0 }; - struct nlmsghdr *header; - struct ifaddrmsg *addmsg; - struct ifinfomsg *infomsg; - struct in_addr *ip_addr; - - src_addr.nl_pid = getpid (); - - if_loopback = (int) if_nametoindex ("lo"); - if (if_loopback <= 0) - return -1; - - rtnl_fd = socket (PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE); - if (rtnl_fd < 0) - return -1; - - r = bind (rtnl_fd, (struct sockaddr *)&src_addr, sizeof (src_addr)); - if (r < 0) - return -1; - - header = rtnl_setup_request (buffer, RTM_NEWADDR, - NLM_F_CREATE|NLM_F_EXCL|NLM_F_ACK, - sizeof (struct ifaddrmsg)); - addmsg = NLMSG_DATA(header); - - addmsg->ifa_family = AF_INET; - addmsg->ifa_prefixlen = 8; - addmsg->ifa_flags = IFA_F_PERMANENT; - addmsg->ifa_scope = RT_SCOPE_HOST; - addmsg->ifa_index = if_loopback; - - ip_addr = add_rta (header, IFA_LOCAL, sizeof (*ip_addr)); - ip_addr->s_addr = htonl(INADDR_LOOPBACK); - - ip_addr = add_rta (header, IFA_ADDRESS, sizeof (*ip_addr)); - ip_addr->s_addr = htonl(INADDR_LOOPBACK); - - assert (header->nlmsg_len < sizeof (buffer)); - - if (rtnl_do_request (rtnl_fd, header)) - return -1; - - header = rtnl_setup_request (buffer, RTM_NEWLINK, - NLM_F_ACK, - sizeof (struct ifinfomsg)); - infomsg = NLMSG_DATA(header); - - infomsg->ifi_family = AF_UNSPEC; - infomsg->ifi_type = 0; - infomsg->ifi_index = if_loopback; - infomsg->ifi_flags = IFF_UP; - infomsg->ifi_change = IFF_UP; - - assert (header->nlmsg_len < sizeof (buffer)); - - if (rtnl_do_request (rtnl_fd, header)) - return -1; - - return 0; -} static void block_sigchild (void) diff --git a/network.c b/network.c new file mode 100644 index 0000000..0534bbe --- /dev/null +++ b/network.c @@ -0,0 +1,200 @@ +/* build-root + * Copyright (C) 2016 Alexander Larsson + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include "config.h" + +#include <arpa/inet.h> +#include <net/if.h> +#include <netinet/in.h> +#include <linux/loop.h> +#include <linux/netlink.h> +#include <linux/rtnetlink.h> + +#include "utils.h" +#include "network.h" + +static void * +add_rta (struct nlmsghdr *header, + int type, + size_t size) +{ + struct rtattr *rta; + size_t rta_size = RTA_LENGTH(size); + + rta = (struct rtattr*)((char *)header + NLMSG_ALIGN(header->nlmsg_len)); + rta->rta_type = type; + rta->rta_len = rta_size; + + header->nlmsg_len = NLMSG_ALIGN(header->nlmsg_len) + rta_size; + + return RTA_DATA(rta); +} + +static int +rtnl_send_request (int rtnl_fd, + struct nlmsghdr *header) +{ + struct sockaddr_nl dst_addr = { AF_NETLINK, 0 }; + ssize_t sent; + + sent = sendto (rtnl_fd, (void *)header, header->nlmsg_len, 0, + (struct sockaddr *)&dst_addr, sizeof (dst_addr)); + if (sent < 0) + return 1; + + return 0; +} + +static int +rtnl_read_reply (int rtnl_fd, + int seq_nr) +{ + char buffer[1024]; + ssize_t received; + struct nlmsghdr *rheader; + + while (1) + { + received = recv (rtnl_fd, buffer, sizeof(buffer), 0); + if (received < 0) + return 1; + + rheader = (struct nlmsghdr *)buffer; + while (received >= NLMSG_HDRLEN) + { + if (rheader->nlmsg_seq != seq_nr) + return 1; + if (rheader->nlmsg_pid != getpid ()) + return 1; + if (rheader->nlmsg_type == NLMSG_ERROR) + { + uint32_t *err = NLMSG_DATA(rheader); + if (*err == 0) + return 0; + + return 1; + } + if (rheader->nlmsg_type == NLMSG_DONE) + return 0; + + rheader = NLMSG_NEXT(rheader, received); + } + } +} + +static int +rtnl_do_request (int rtnl_fd, + struct nlmsghdr *header) +{ + if (!rtnl_send_request (rtnl_fd, header)) + return 1; + + if (!rtnl_read_reply (rtnl_fd, header->nlmsg_seq)) + return 1; + + return 0; +} + +static struct nlmsghdr * +rtnl_setup_request (char *buffer, + int type, + int flags, + size_t size) +{ + struct nlmsghdr *header; + size_t len = NLMSG_LENGTH (size); + static uint32_t counter = 0; + + memset (buffer, 0, len); + + header = (struct nlmsghdr *)buffer; + header->nlmsg_len = len; + header->nlmsg_type = type; + header->nlmsg_flags = flags | NLM_F_REQUEST; + header->nlmsg_seq = counter++; + header->nlmsg_pid = getpid (); + + return (struct nlmsghdr *)header; +} + +int +loopback_setup (void) +{ + int r, if_loopback; + cleanup_fd int rtnl_fd = -1; + char buffer[1024]; + struct sockaddr_nl src_addr = { AF_NETLINK, 0 }; + struct nlmsghdr *header; + struct ifaddrmsg *addmsg; + struct ifinfomsg *infomsg; + struct in_addr *ip_addr; + + src_addr.nl_pid = getpid (); + + if_loopback = (int) if_nametoindex ("lo"); + if (if_loopback <= 0) + return -1; + + rtnl_fd = socket (PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE); + if (rtnl_fd < 0) + return -1; + + r = bind (rtnl_fd, (struct sockaddr *)&src_addr, sizeof (src_addr)); + if (r < 0) + return -1; + + header = rtnl_setup_request (buffer, RTM_NEWADDR, + NLM_F_CREATE|NLM_F_EXCL|NLM_F_ACK, + sizeof (struct ifaddrmsg)); + addmsg = NLMSG_DATA(header); + + addmsg->ifa_family = AF_INET; + addmsg->ifa_prefixlen = 8; + addmsg->ifa_flags = IFA_F_PERMANENT; + addmsg->ifa_scope = RT_SCOPE_HOST; + addmsg->ifa_index = if_loopback; + + ip_addr = add_rta (header, IFA_LOCAL, sizeof (*ip_addr)); + ip_addr->s_addr = htonl(INADDR_LOOPBACK); + + ip_addr = add_rta (header, IFA_ADDRESS, sizeof (*ip_addr)); + ip_addr->s_addr = htonl(INADDR_LOOPBACK); + + assert (header->nlmsg_len < sizeof (buffer)); + + if (rtnl_do_request (rtnl_fd, header)) + return -1; + + header = rtnl_setup_request (buffer, RTM_NEWLINK, + NLM_F_ACK, + sizeof (struct ifinfomsg)); + infomsg = NLMSG_DATA(header); + + infomsg->ifi_family = AF_UNSPEC; + infomsg->ifi_type = 0; + infomsg->ifi_index = if_loopback; + infomsg->ifi_flags = IFF_UP; + infomsg->ifi_change = IFF_UP; + + assert (header->nlmsg_len < sizeof (buffer)); + + if (rtnl_do_request (rtnl_fd, header)) + return -1; + + return 0; +} diff --git a/network.h b/network.h new file mode 100644 index 0000000..cf06779 --- /dev/null +++ b/network.h @@ -0,0 +1,24 @@ +/* build-root + * Copyright (C) 2016 Alexander Larsson + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#ifndef __NETWORK_H__ +#define __NETWORK_H__ + +int loopback_setup (void); + +#endif /* __NETWORK_H__ */ |