[821] | 1 | /*
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| 2 | * libnetlink.c RTnetlink service routines.
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| 3 | *
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| 4 | * This program is free software; you can redistribute it and/or
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| 5 | * modify it under the terms of the GNU General Public License
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| 6 | * as published by the Free Software Foundation; either version
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| 7 | * 2 of the License, or (at your option) any later version.
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| 8 | *
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| 9 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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| 10 | *
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| 11 | */
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| 12 |
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| 13 | #include "libbb.h"
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| 14 | #include <sys/socket.h>
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| 15 |
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| 16 | #include <errno.h>
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| 17 | #include <string.h>
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| 18 | #include <time.h>
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| 19 | #include <unistd.h>
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| 20 |
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| 21 | #include <sys/uio.h>
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| 22 |
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| 23 | #include "libnetlink.h"
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| 24 |
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| 25 | void rtnl_close(struct rtnl_handle *rth)
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| 26 | {
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| 27 | close(rth->fd);
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| 28 | }
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| 29 |
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| 30 | int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
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| 31 | {
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| 32 | socklen_t addr_len;
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| 33 |
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| 34 | memset(rth, 0, sizeof(rth));
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| 35 |
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| 36 | rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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| 37 | if (rth->fd < 0) {
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| 38 | bb_perror_msg("Cannot open netlink socket");
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| 39 | return -1;
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| 40 | }
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| 41 |
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| 42 | memset(&rth->local, 0, sizeof(rth->local));
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| 43 | rth->local.nl_family = AF_NETLINK;
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| 44 | rth->local.nl_groups = subscriptions;
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| 45 |
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| 46 | if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) {
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| 47 | bb_perror_msg("Cannot bind netlink socket");
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| 48 | return -1;
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| 49 | }
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| 50 | addr_len = sizeof(rth->local);
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| 51 | if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {
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| 52 | bb_perror_msg("Cannot getsockname");
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| 53 | return -1;
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| 54 | }
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| 55 | if (addr_len != sizeof(rth->local)) {
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| 56 | bb_error_msg("Wrong address length %d", addr_len);
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| 57 | return -1;
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| 58 | }
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| 59 | if (rth->local.nl_family != AF_NETLINK) {
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| 60 | bb_error_msg("Wrong address family %d", rth->local.nl_family);
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| 61 | return -1;
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| 62 | }
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| 63 | rth->seq = time(NULL);
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| 64 | return 0;
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| 65 | }
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| 66 |
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| 67 | int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
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| 68 | {
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| 69 | struct {
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| 70 | struct nlmsghdr nlh;
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| 71 | struct rtgenmsg g;
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| 72 | } req;
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| 73 | struct sockaddr_nl nladdr;
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| 74 |
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| 75 | memset(&nladdr, 0, sizeof(nladdr));
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| 76 | nladdr.nl_family = AF_NETLINK;
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| 77 |
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| 78 | req.nlh.nlmsg_len = sizeof(req);
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| 79 | req.nlh.nlmsg_type = type;
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| 80 | req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
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| 81 | req.nlh.nlmsg_pid = 0;
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| 82 | req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
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| 83 | req.g.rtgen_family = family;
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| 84 |
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| 85 | return sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr));
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| 86 | }
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| 87 |
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| 88 | int rtnl_send(struct rtnl_handle *rth, char *buf, int len)
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| 89 | {
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| 90 | struct sockaddr_nl nladdr;
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| 91 |
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| 92 | memset(&nladdr, 0, sizeof(nladdr));
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| 93 | nladdr.nl_family = AF_NETLINK;
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| 94 |
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| 95 | return sendto(rth->fd, buf, len, 0, (struct sockaddr*)&nladdr, sizeof(nladdr));
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| 96 | }
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| 97 |
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| 98 | int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
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| 99 | {
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| 100 | struct nlmsghdr nlh;
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| 101 | struct sockaddr_nl nladdr;
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| 102 | struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } };
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| 103 | struct msghdr msg = {
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| 104 | (void*)&nladdr, sizeof(nladdr),
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| 105 | iov, 2,
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| 106 | NULL, 0,
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| 107 | 0
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| 108 | };
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| 109 |
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| 110 | memset(&nladdr, 0, sizeof(nladdr));
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| 111 | nladdr.nl_family = AF_NETLINK;
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| 112 |
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| 113 | nlh.nlmsg_len = NLMSG_LENGTH(len);
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| 114 | nlh.nlmsg_type = type;
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| 115 | nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
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| 116 | nlh.nlmsg_pid = 0;
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| 117 | nlh.nlmsg_seq = rth->dump = ++rth->seq;
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| 118 |
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| 119 | return sendmsg(rth->fd, &msg, 0);
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| 120 | }
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| 121 |
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| 122 | int rtnl_dump_filter(struct rtnl_handle *rth,
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| 123 | int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
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| 124 | void *arg1,
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| 125 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
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| 126 | void *arg2)
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| 127 | {
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| 128 | char buf[8192];
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| 129 | struct sockaddr_nl nladdr;
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| 130 | struct iovec iov = { buf, sizeof(buf) };
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| 131 |
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| 132 | while (1) {
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| 133 | int status;
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| 134 | struct nlmsghdr *h;
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| 135 |
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| 136 | struct msghdr msg = {
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| 137 | (void*)&nladdr, sizeof(nladdr),
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| 138 | &iov, 1,
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| 139 | NULL, 0,
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| 140 | 0
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| 141 | };
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| 142 |
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| 143 | status = recvmsg(rth->fd, &msg, 0);
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| 144 |
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| 145 | if (status < 0) {
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| 146 | if (errno == EINTR)
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| 147 | continue;
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| 148 | bb_perror_msg("OVERRUN");
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| 149 | continue;
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| 150 | }
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| 151 | if (status == 0) {
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| 152 | bb_error_msg("EOF on netlink");
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| 153 | return -1;
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| 154 | }
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| 155 | if (msg.msg_namelen != sizeof(nladdr)) {
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| 156 | bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
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| 157 | }
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| 158 |
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| 159 | h = (struct nlmsghdr*)buf;
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| 160 | while (NLMSG_OK(h, status)) {
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| 161 | int err;
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| 162 |
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| 163 | if (nladdr.nl_pid != 0 ||
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| 164 | h->nlmsg_pid != rth->local.nl_pid ||
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| 165 | h->nlmsg_seq != rth->dump) {
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| 166 | if (junk) {
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| 167 | err = junk(&nladdr, h, arg2);
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| 168 | if (err < 0) {
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| 169 | return err;
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| 170 | }
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| 171 | }
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| 172 | goto skip_it;
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| 173 | }
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| 174 |
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| 175 | if (h->nlmsg_type == NLMSG_DONE) {
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| 176 | return 0;
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| 177 | }
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| 178 | if (h->nlmsg_type == NLMSG_ERROR) {
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| 179 | struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
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| 180 | if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
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| 181 | bb_error_msg("ERROR truncated");
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| 182 | } else {
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| 183 | errno = -l_err->error;
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| 184 | bb_perror_msg("RTNETLINK answers");
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| 185 | }
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| 186 | return -1;
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| 187 | }
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| 188 | err = filter(&nladdr, h, arg1);
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| 189 | if (err < 0) {
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| 190 | return err;
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| 191 | }
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| 192 |
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| 193 | skip_it:
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| 194 | h = NLMSG_NEXT(h, status);
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| 195 | }
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| 196 | if (msg.msg_flags & MSG_TRUNC) {
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| 197 | bb_error_msg("Message truncated");
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| 198 | continue;
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| 199 | }
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| 200 | if (status) {
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| 201 | bb_error_msg_and_die("!!!Remnant of size %d", status);
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| 202 | }
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| 203 | }
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| 204 | }
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| 205 |
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| 206 | int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
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| 207 | unsigned groups, struct nlmsghdr *answer,
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| 208 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
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| 209 | void *jarg)
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| 210 | {
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| 211 | int status;
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| 212 | unsigned seq;
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| 213 | struct nlmsghdr *h;
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| 214 | struct sockaddr_nl nladdr;
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| 215 | struct iovec iov = { (void*)n, n->nlmsg_len };
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| 216 | char buf[8192];
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| 217 | struct msghdr msg = {
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| 218 | (void*)&nladdr, sizeof(nladdr),
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| 219 | &iov, 1,
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| 220 | NULL, 0,
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| 221 | 0
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| 222 | };
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| 223 |
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| 224 | memset(&nladdr, 0, sizeof(nladdr));
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| 225 | nladdr.nl_family = AF_NETLINK;
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| 226 | nladdr.nl_pid = peer;
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| 227 | nladdr.nl_groups = groups;
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| 228 |
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| 229 | n->nlmsg_seq = seq = ++rtnl->seq;
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| 230 | if (answer == NULL) {
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| 231 | n->nlmsg_flags |= NLM_F_ACK;
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| 232 | }
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| 233 | status = sendmsg(rtnl->fd, &msg, 0);
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| 234 |
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| 235 | if (status < 0) {
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| 236 | bb_perror_msg("Cannot talk to rtnetlink");
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| 237 | return -1;
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| 238 | }
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| 239 |
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| 240 | iov.iov_base = buf;
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| 241 |
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| 242 | while (1) {
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| 243 | iov.iov_len = sizeof(buf);
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| 244 | status = recvmsg(rtnl->fd, &msg, 0);
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| 245 |
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| 246 | if (status < 0) {
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| 247 | if (errno == EINTR) {
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| 248 | continue;
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| 249 | }
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| 250 | bb_perror_msg("OVERRUN");
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| 251 | continue;
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| 252 | }
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| 253 | if (status == 0) {
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| 254 | bb_error_msg("EOF on netlink");
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| 255 | return -1;
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| 256 | }
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| 257 | if (msg.msg_namelen != sizeof(nladdr)) {
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| 258 | bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
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| 259 | }
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| 260 | for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
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| 261 | int l_err;
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| 262 | int len = h->nlmsg_len;
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| 263 | int l = len - sizeof(*h);
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| 264 |
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| 265 | if (l<0 || len>status) {
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| 266 | if (msg.msg_flags & MSG_TRUNC) {
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| 267 | bb_error_msg("Truncated message");
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| 268 | return -1;
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| 269 | }
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| 270 | bb_error_msg_and_die("!!!malformed message: len=%d", len);
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| 271 | }
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| 272 |
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| 273 | if (nladdr.nl_pid != peer ||
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| 274 | h->nlmsg_pid != rtnl->local.nl_pid ||
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| 275 | h->nlmsg_seq != seq) {
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| 276 | if (junk) {
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| 277 | l_err = junk(&nladdr, h, jarg);
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| 278 | if (l_err < 0) {
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| 279 | return l_err;
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| 280 | }
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| 281 | }
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| 282 | continue;
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| 283 | }
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| 284 |
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| 285 | if (h->nlmsg_type == NLMSG_ERROR) {
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| 286 | struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
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| 287 | if (l < sizeof(struct nlmsgerr)) {
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| 288 | bb_error_msg("ERROR truncated");
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| 289 | } else {
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| 290 | errno = -err->error;
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| 291 | if (errno == 0) {
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| 292 | if (answer) {
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| 293 | memcpy(answer, h, h->nlmsg_len);
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| 294 | }
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| 295 | return 0;
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| 296 | }
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| 297 | bb_perror_msg("RTNETLINK answers");
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| 298 | }
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| 299 | return -1;
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| 300 | }
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| 301 | if (answer) {
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| 302 | memcpy(answer, h, h->nlmsg_len);
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| 303 | return 0;
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| 304 | }
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| 305 |
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| 306 | bb_error_msg("Unexpected reply!!!");
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| 307 |
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| 308 | status -= NLMSG_ALIGN(len);
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| 309 | h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
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| 310 | }
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| 311 | if (msg.msg_flags & MSG_TRUNC) {
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| 312 | bb_error_msg("Message truncated");
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| 313 | continue;
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| 314 | }
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| 315 | if (status) {
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| 316 | bb_error_msg_and_die("!!!Remnant of size %d", status);
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| 317 | }
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| 318 | }
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| 319 | }
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| 320 |
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| 321 | int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
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| 322 | {
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| 323 | int len = RTA_LENGTH(4);
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| 324 | struct rtattr *rta;
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| 325 | if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
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| 326 | return -1;
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| 327 | rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
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| 328 | rta->rta_type = type;
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| 329 | rta->rta_len = len;
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| 330 | memcpy(RTA_DATA(rta), &data, 4);
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| 331 | n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
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| 332 | return 0;
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| 333 | }
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| 334 |
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| 335 | int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
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| 336 | {
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| 337 | int len = RTA_LENGTH(alen);
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| 338 | struct rtattr *rta;
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| 339 |
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| 340 | if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
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| 341 | return -1;
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| 342 | rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
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| 343 | rta->rta_type = type;
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| 344 | rta->rta_len = len;
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| 345 | memcpy(RTA_DATA(rta), data, alen);
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| 346 | n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
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| 347 | return 0;
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| 348 | }
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| 349 |
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| 350 | int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
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| 351 | {
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| 352 | int len = RTA_LENGTH(4);
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| 353 | struct rtattr *subrta;
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| 354 |
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| 355 | if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
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| 356 | return -1;
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| 357 | }
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| 358 | subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
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| 359 | subrta->rta_type = type;
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| 360 | subrta->rta_len = len;
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| 361 | memcpy(RTA_DATA(subrta), &data, 4);
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| 362 | rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
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| 363 | return 0;
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| 364 | }
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| 365 |
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| 366 | int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
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| 367 | {
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| 368 | struct rtattr *subrta;
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| 369 | int len = RTA_LENGTH(alen);
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| 370 |
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| 371 | if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
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| 372 | return -1;
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| 373 | }
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| 374 | subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
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| 375 | subrta->rta_type = type;
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| 376 | subrta->rta_len = len;
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| 377 | memcpy(RTA_DATA(subrta), data, alen);
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| 378 | rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
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| 379 | return 0;
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| 380 | }
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| 381 |
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| 382 |
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| 383 | int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
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| 384 | {
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| 385 | while (RTA_OK(rta, len)) {
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| 386 | if (rta->rta_type <= max) {
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| 387 | tb[rta->rta_type] = rta;
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| 388 | }
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| 389 | rta = RTA_NEXT(rta,len);
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| 390 | }
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| 391 | if (len) {
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| 392 | bb_error_msg("!!!Deficit %d, rta_len=%d", len, rta->rta_len);
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| 393 | }
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| 394 | return 0;
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| 395 | }
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