1 /* NHRP netlink/GRE tunnel configuration code
2 * Copyright (c) 2014-2016 Timo Teräs
3 *
4 * This file is free software: you may copy, redistribute and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 2 of the License, or
7 * (at your option) any later version.
8 */
9
10 #include <sys/socket.h>
11 #include <linux/netlink.h>
12 #include <linux/rtnetlink.h>
13 #include <linux/in.h>
14 #include <linux/if.h>
15 #include <linux/ip.h>
16 #include <linux/ipv6.h>
17 #include <linux/if_tunnel.h>
18
19 #include "debug.h"
20 #include "netlink.h"
21 #include "znl.h"
22
__netlink_gre_get_data(struct zbuf * zb,struct zbuf * data,int ifindex)23 static int __netlink_gre_get_data(struct zbuf *zb, struct zbuf *data, int ifindex)
24 {
25 struct nlmsghdr *n;
26 struct ifinfomsg *ifi;
27 struct zbuf payload, rtapayload;
28 struct rtattr *rta;
29
30 debugf(NHRP_DEBUG_KERNEL, "netlink-link-gre: get-info %u", ifindex);
31
32 n = znl_nlmsg_push(zb, RTM_GETLINK, NLM_F_REQUEST);
33 ifi = znl_push(zb, sizeof(*ifi));
34 *ifi = (struct ifinfomsg) {
35 .ifi_index = ifindex,
36 };
37 znl_nlmsg_complete(zb, n);
38
39 if (zbuf_send(zb, netlink_req_fd) < 0 ||
40 zbuf_recv(zb, netlink_req_fd) < 0)
41 return -1;
42
43 n = znl_nlmsg_pull(zb, &payload);
44 if (!n) return -1;
45
46 if (n->nlmsg_type != RTM_NEWLINK)
47 return -1;
48
49 ifi = znl_pull(&payload, sizeof(struct ifinfomsg));
50 if (!ifi)
51 return -1;
52
53 debugf(NHRP_DEBUG_KERNEL, "netlink-link-gre: ifindex %u, receive msg_type %u, msg_flags %u",
54 ifi->ifi_index, n->nlmsg_type, n->nlmsg_flags);
55
56 if (ifi->ifi_index != ifindex)
57 return -1;
58
59 while ((rta = znl_rta_pull(&payload, &rtapayload)) != NULL)
60 if (rta->rta_type == IFLA_LINKINFO)
61 break;
62 if (!rta) return -1;
63
64 payload = rtapayload;
65 while ((rta = znl_rta_pull(&payload, &rtapayload)) != NULL)
66 if (rta->rta_type == IFLA_INFO_DATA)
67 break;
68 if (!rta) return -1;
69
70 *data = rtapayload;
71 return 0;
72 }
73
netlink_gre_get_info(unsigned int ifindex,uint32_t * gre_key,unsigned int * link_index,struct in_addr * saddr)74 void netlink_gre_get_info(unsigned int ifindex, uint32_t *gre_key, unsigned int *link_index, struct in_addr *saddr)
75 {
76 struct zbuf *zb = zbuf_alloc(8192), data, rtapl;
77 struct rtattr *rta;
78
79 *link_index = 0;
80 *gre_key = 0;
81 saddr->s_addr = 0;
82
83 if (__netlink_gre_get_data(zb, &data, ifindex) < 0)
84 goto err;
85
86 while ((rta = znl_rta_pull(&data, &rtapl)) != NULL) {
87 switch (rta->rta_type) {
88 case IFLA_GRE_LINK:
89 *link_index = zbuf_get32(&rtapl);
90 break;
91 case IFLA_GRE_IKEY:
92 case IFLA_GRE_OKEY:
93 *gre_key = zbuf_get32(&rtapl);
94 break;
95 case IFLA_GRE_LOCAL:
96 saddr->s_addr = zbuf_get32(&rtapl);
97 break;
98 }
99 }
100 err:
101 zbuf_free(zb);
102 }
103
netlink_gre_set_link(unsigned int ifindex,unsigned int link_index)104 void netlink_gre_set_link(unsigned int ifindex, unsigned int link_index)
105 {
106 struct nlmsghdr *n;
107 struct ifinfomsg *ifi;
108 struct rtattr *rta_info, *rta_data, *rta;
109 struct zbuf *zr = zbuf_alloc(8192), data, rtapl;
110 struct zbuf *zb = zbuf_alloc(8192);
111 size_t len;
112
113 if (__netlink_gre_get_data(zr, &data, ifindex) < 0)
114 goto err;
115
116 n = znl_nlmsg_push(zb, RTM_NEWLINK, NLM_F_REQUEST);
117 ifi = znl_push(zb, sizeof(*ifi));
118 *ifi = (struct ifinfomsg) {
119 .ifi_index = ifindex,
120 };
121 rta_info = znl_rta_nested_push(zb, IFLA_LINKINFO);
122 znl_rta_push(zb, IFLA_INFO_KIND, "gre", 3);
123 rta_data = znl_rta_nested_push(zb, IFLA_INFO_DATA);
124
125 znl_rta_push_u32(zb, IFLA_GRE_LINK, link_index);
126 while ((rta = znl_rta_pull(&data, &rtapl)) != NULL) {
127 if (rta->rta_type == IFLA_GRE_LINK)
128 continue;
129 len = zbuf_used(&rtapl);
130 znl_rta_push(zb, rta->rta_type, zbuf_pulln(&rtapl, len), len);
131 }
132
133 znl_rta_nested_complete(zb, rta_data);
134 znl_rta_nested_complete(zb, rta_info);
135
136 znl_nlmsg_complete(zb, n);
137 zbuf_send(zb, netlink_req_fd);
138 zbuf_recv(zb, netlink_req_fd);
139 err:
140 zbuf_free(zb);
141 zbuf_free(zr);
142 }
143