diff --git a/doc/route.txt b/doc/route.txt index 746201a..f70ad87 100644 --- a/doc/route.txt +++ b/doc/route.txt @@ -1002,6 +1002,84 @@ if((err = rtnl_link_add(sk, link, NLM_F_CREATE)) < 0) rtnl_link_put(link); ----- +[[link_sit]] +==== SIT + +[source,c] +----- +extern struct rtnl_link *rtnl_link_sit_alloc(void); +extern int rtnl_link_sit_add(struct nl_sock *sk, const char *name); + +extern int rtnl_link_sit_set_link(struct rtnl_link *link, uint32_t index); +extern uint32_t rtnl_link_sit_get_link(struct rtnl_link *link); + +extern int rtnl_link_sit_set_iflags(struct rtnl_link *link, uint16_t iflags); +extern uint16_t rtnl_link_get_iflags(struct rtnl_link *link); + +extern int rtnl_link_sit_set_oflags(struct rtnl_link *link, uint16_t oflags); +extern uint16_t rtnl_link_get_oflags(struct rtnl_link *link); + +extern int rtnl_link_sit_set_ikey(struct rtnl_link *link, uint32_t ikey); +extern uint32_t rtnl_link_get_ikey(struct rtnl_link *link); + +extern int rtnl_link_sit_set_okey(struct rtnl_link *link, uint32_t okey); +extern uint32_t rtnl_link_get_okey(struct rtnl_link *link) + +extern int rtnl_link_sit_set_local(struct rtnl_link *link, uint32_t addr); +extern uint32_t rtnl_link_sit_get_local(struct rtnl_link *link); + +extern int rtnl_link_sit_set_remote(struct rtnl_link *link, uint32_t addr); +extern uint32_t rtnl_link_sit_get_remote(struct rtnl_link *link); + +extern int rtnl_link_sit_set_ttl(struct rtnl_link *link, uint8_t ttl); +extern uint8_t rtnl_link_sit_get_ttl(struct rtnl_link *link); + +extern int rtnl_link_sit_set_tos(struct rtnl_link *link, uint8_t tos); +extern uint8_t rtnl_link_sit_get_tos(struct rtnl_link *link); + +extern int rtnl_link_sit_set_pmtudisc(struct rtnl_link *link, uint8_t pmtudisc); +extern uint8_t rtnl_link_sit_get_pmtudisc(struct rtnl_link *link); + +----- + +.Example: Add a sit tunnel device +[source,c] +----- +struct rtnl_link *link +struct in_addr addr + +/* allocate new link object of type vxlan */ +if(!(link = rtnl_link_sit_alloc())) + /* error */ + +/* set sit tunnel name */ +if ((err = rtnl_link_set_name(link, "sit-tun")) < 0) + /* error */ + +/* set link index */ +if ((err = rtnl_link_sit_set_link(link, if_index)) < 0) + /* error */ + +/* set local address */ +inet_pton(AF_INET, "192.168.254.12", &addr.s_addr); +if ((err = rtnl_link_sit_set_local(link, addr.s_addr)) < 0) + /* error */ + +/* set remote address */ +inet_pton(AF_INET, "192.168.254.13", &addr.s_addr +if ((err = rtnl_link_sit_set_remote(link, addr.s_addr)) < 0) + /* error */ + +/* set tunnel ttl */ +if ((err = rtnl_link_sit_set_ttl(link, 64)) < 0) + /* error */ + +if((err = rtnl_link_add(sk, link, NLM_F_CREATE)) < 0) + /* error */ + +rtnl_link_put(link); +----- + == Neighbouring diff --git a/include/Makefile.am b/include/Makefile.am index eb205f7..f957d1d 100644 --- a/include/Makefile.am +++ b/include/Makefile.am @@ -55,6 +55,7 @@ nobase_libnlinclude_HEADERS = \ netlink/route/link/veth.h \ netlink/route/link/ipgre.h \ netlink/route/link/ipip.h \ + netlink/route/link/sit.h \ netlink/route/qdisc/cbq.h \ netlink/route/qdisc/dsmark.h \ netlink/route/qdisc/fifo.h \ diff --git a/include/netlink/route/link/sit.h b/include/netlink/route/link/sit.h new file mode 100644 index 0000000..84dc44a --- /dev/null +++ b/include/netlink/route/link/sit.h @@ -0,0 +1,53 @@ +/* + * netlink/route/link/sit.h SIT interface + * + * This library 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 version 2.1 + * of the License. + * + * Copyright (c) 2014 Susant Sahani + */ + +#ifndef NETLINK_LINK_SIT_H_ +#define NETLINK_LINK_SIT_H_ + +#include +#include + +#ifdef __cplusplus +extern "C" { +#endif + + extern struct rtnl_link *rtnl_link_sit_alloc(void); + extern int rtnl_link_sit_add(struct nl_sock *sk, const char *name); + + extern int rtnl_link_sit_set_link(struct rtnl_link *link, uint32_t index); + extern uint32_t rtnl_link_sit_get_link(struct rtnl_link *link); + + extern int rtnl_link_sit_set_local(struct rtnl_link *link, uint32_t addr); + extern uint32_t rtnl_link_get_sit_local(struct rtnl_link *link); + + extern int rtnl_link_sit_set_remote(struct rtnl_link *link, uint32_t addr); + extern uint32_t rtnl_link_sit_get_remote(struct rtnl_link *link); + + extern int rtnl_link_sit_set_ttl(struct rtnl_link *link, uint8_t ttl); + extern uint8_t rtnl_link_sit_get_ttl(struct rtnl_link *link); + + extern int rtnl_link_sit_set_tos(struct rtnl_link *link, uint8_t tos); + extern uint8_t rtnl_link_sit_get_tos(struct rtnl_link *link); + + extern int rtnl_link_sit_set_pmtudisc(struct rtnl_link *link, uint8_t pmtudisc); + extern uint8_t rtnl_link_sit_get_pmtudisc(struct rtnl_link *link); + + extern int rtnl_link_sit_set_flags(struct rtnl_link *link, uint16_t flags); + extern uint16_t rtnl_link_sit_get_flags(struct rtnl_link *link); + + int rtnl_link_sit_set_proto(struct rtnl_link *link, uint8_t proto); + uint8_t rtnl_link_get_proto(struct rtnl_link *link); + +#ifdef _cplusplus +} +#endif + +#endif diff --git a/lib/Makefile.am b/lib/Makefile.am index 92ba0c6..ae35a96 100644 --- a/lib/Makefile.am +++ b/lib/Makefile.am @@ -79,7 +79,7 @@ libnl_route_3_la_SOURCES = \ route/link/bridge.c route/link/inet6.c route/link/inet.c \ route/link/bonding.c route/link/can.c route/link/macvlan.c \ route/link/vxlan.c route/link/veth.c route/link/ipip.c \ - route/link/ipgre.c \ + route/link/ipgre.c route/link/sit.c\ \ route/qdisc/blackhole.c route/qdisc/cbq.c route/qdisc/dsmark.c \ route/qdisc/fifo.c route/qdisc/htb.c route/qdisc/netem.c \ diff --git a/lib/route/link/sit.c b/lib/route/link/sit.c new file mode 100644 index 0000000..694c177 --- /dev/null +++ b/lib/route/link/sit.c @@ -0,0 +1,624 @@ +/* + * lib/route/link/sit.c SIT Link Info + * + * This library 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 version 2.1 + * of the License. + * + * Copyright (c) 2014 Susant Sahani + */ + +/** + * @ingroup link + * @defgroup sit SIT + * sit link module + * + * @details + * \b Link Type Name: "sit" + * + * @route_doc{link_sit, SIT Documentation} + * + * @{ + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define SIT_ATTR_LINK (1 << 0) +#define SIT_ATTR_LOCAL (1 << 1) +#define SIT_ATTR_REMOTE (1 << 2) +#define SIT_ATTR_TTL (1 << 3) +#define SIT_ATTR_TOS (1 << 4) +#define SIT_ATTR_PMTUDISC (1 << 5) +#define SIT_ATTR_FLAGS (1 << 6) +#define SIT_ATTR_PROTO (1 << 7) + +struct sit_info +{ + uint8_t ttl; + uint8_t tos; + uint8_t pmtudisc; + uint8_t proto; + uint16_t flags; + uint32_t link; + uint32_t local; + uint32_t remote; + uint32_t sit_mask; +}; + +static struct nla_policy sit_policy[IFLA_IPTUN_MAX + 1] = { + [IFLA_IPTUN_LINK] = { .type = NLA_U32 }, + [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 }, + [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 }, + [IFLA_IPTUN_TTL] = { .type = NLA_U8 }, + [IFLA_IPTUN_TOS] = { .type = NLA_U8 }, + [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 }, + [IFLA_IPTUN_FLAGS] = { .type = NLA_U16 }, + [IFLA_IPTUN_PROTO] = { .type = NLA_U8 }, +}; + +static int sit_alloc(struct rtnl_link *link) +{ + struct sit_info *sit; + + sit = calloc(1, sizeof(*sit)); + if (!sit) + return -NLE_NOMEM; + + link->l_info = sit; + + return 0; +} + +static int sit_parse(struct rtnl_link *link, struct nlattr *data, + struct nlattr *xstats) +{ + struct nlattr *tb[IFLA_IPTUN_MAX + 1]; + struct sit_info *sit; + int err; + + NL_DBG(3, "Parsing SIT link info"); + + err = nla_parse_nested(tb, IFLA_IPTUN_MAX, data, sit_policy); + if (err < 0) + goto errout; + + err = sit_alloc(link); + if (err < 0) + goto errout; + + sit = link->l_info; + + if (tb[IFLA_IPTUN_LINK]) { + sit->link = nla_get_u32(tb[IFLA_IPTUN_LINK]); + sit->sit_mask |= SIT_ATTR_LINK; + } + + if (tb[IFLA_IPTUN_LOCAL]) { + sit->local = nla_get_u32(tb[IFLA_IPTUN_LOCAL]); + sit->sit_mask |= SIT_ATTR_LOCAL; + } + + if (tb[IFLA_IPTUN_REMOTE]) { + sit->remote = nla_get_u32(tb[IFLA_IPTUN_REMOTE]); + sit->sit_mask |= SIT_ATTR_REMOTE; + } + + if (tb[IFLA_IPTUN_TTL]) { + sit->ttl = nla_get_u8(tb[IFLA_IPTUN_TTL]); + sit->sit_mask |= SIT_ATTR_TTL; + } + + if (tb[IFLA_IPTUN_TOS]) { + sit->tos = nla_get_u8(tb[IFLA_IPTUN_TOS]); + sit->sit_mask |= SIT_ATTR_TOS; + } + + if (tb[IFLA_IPTUN_PMTUDISC]) { + sit->pmtudisc = nla_get_u8(tb[IFLA_IPTUN_PMTUDISC]); + sit->sit_mask |= SIT_ATTR_PMTUDISC; + } + + if (tb[IFLA_IPTUN_FLAGS]) { + sit->flags = nla_get_u16(tb[IFLA_IPTUN_FLAGS]); + sit->sit_mask |= SIT_ATTR_FLAGS; + } + + if (tb[IFLA_IPTUN_PROTO]) { + sit->proto = nla_get_u8(tb[IFLA_IPTUN_PROTO]); + sit->sit_mask |= SIT_ATTR_PROTO; + } + + err = 0; + + errout: + return err; +} + +static int sit_put_attrs(struct nl_msg *msg, struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + struct nlattr *data; + + data = nla_nest_start(msg, IFLA_INFO_DATA); + if (!data) + return -NLE_MSGSIZE; + + if (sit->sit_mask & SIT_ATTR_LINK) + NLA_PUT_U32(msg, IFLA_IPTUN_LINK, sit->link); + + if (sit->sit_mask & SIT_ATTR_LOCAL) + NLA_PUT_U32(msg, IFLA_IPTUN_LOCAL, sit->local); + + if (sit->sit_mask & SIT_ATTR_REMOTE) + NLA_PUT_U32(msg, IFLA_IPTUN_REMOTE, sit->remote); + + if (sit->sit_mask & SIT_ATTR_TTL) + NLA_PUT_U8(msg, IFLA_IPTUN_TTL, sit->ttl); + + if (sit->sit_mask & SIT_ATTR_TOS) + NLA_PUT_U8(msg, IFLA_IPTUN_TOS, sit->tos); + + if (sit->sit_mask & SIT_ATTR_PMTUDISC) + NLA_PUT_U8(msg, IFLA_IPTUN_PMTUDISC, sit->pmtudisc); + + if (sit->sit_mask & SIT_ATTR_FLAGS) + NLA_PUT_U16(msg, IFLA_IPTUN_FLAGS, sit->flags); + + if (sit->sit_mask & SIT_ATTR_PROTO) + NLA_PUT_U8(msg, IFLA_IPTUN_PROTO, sit->proto); + + nla_nest_end(msg, data); + +nla_put_failure: + + return 0; +} + +static void sit_free(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + free(sit); + link->l_info = NULL; +} + +static void sit_dump_line(struct rtnl_link *link, struct nl_dump_params *p) +{ + nl_dump(p, "sit : %s", link->l_name); +} + +static void sit_dump_details(struct rtnl_link *link, struct nl_dump_params *p) +{ + struct sit_info *sit = link->l_info; + char *name, addr[INET_ADDRSTRLEN]; + + if (sit->sit_mask & SIT_ATTR_LINK) { + nl_dump(p, " link "); + name = rtnl_link_get_name(link); + if (name) + nl_dump_line(p, "%s\n", name); + else + nl_dump_line(p, "%u\n", sit->link); + } + + if (sit->sit_mask & SIT_ATTR_LOCAL) { + nl_dump(p, " local "); + if(inet_ntop(AF_INET, &sit->local, addr, sizeof(addr))) + nl_dump_line(p, "%s\n", addr); + else + nl_dump_line(p, "%#x\n", ntohs(sit->local)); + } + + if (sit->sit_mask & SIT_ATTR_REMOTE) { + nl_dump(p, " remote "); + if(inet_ntop(AF_INET, &sit->remote, addr, sizeof(addr))) + nl_dump_line(p, "%s\n", addr); + else + nl_dump_line(p, "%#x\n", ntohs(sit->remote)); + } + + if (sit->sit_mask & SIT_ATTR_TTL) { + nl_dump(p, " ttl "); + nl_dump_line(p, "%u\n", sit->ttl); + } + + if (sit->sit_mask & SIT_ATTR_TOS) { + nl_dump(p, " tos "); + nl_dump_line(p, "%u\n", sit->tos); + } + + if (sit->sit_mask & SIT_ATTR_FLAGS) { + nl_dump(p, " flags "); + nl_dump_line(p, " (%x)\n", sit->flags); + } + + if (sit->sit_mask & SIT_ATTR_PROTO) { + nl_dump(p, " proto "); + nl_dump_line(p, " (%x)\n", sit->proto); + } +} + +static int sit_clone(struct rtnl_link *dst, struct rtnl_link *src) +{ + struct sit_info *sit_dst, *sit_src = src->l_info; + int err; + + dst->l_info = NULL; + + err = rtnl_link_set_type(dst, "sit"); + if (err < 0) + return err; + + sit_dst = dst->l_info; + + if (!sit_dst || !sit_src) + return -NLE_NOMEM; + + memcpy(sit_dst, sit_src, sizeof(struct sit_info)); + + return 0; +} + +static struct rtnl_link_info_ops sit_info_ops = { + .io_name = "sit", + .io_alloc = sit_alloc, + .io_parse = sit_parse, + .io_dump = { + [NL_DUMP_LINE] = sit_dump_line, + [NL_DUMP_DETAILS] = sit_dump_details, + }, + .io_clone = sit_clone, + .io_put_attrs = sit_put_attrs, + .io_free = sit_free, +}; + +#define IS_SIT_LINK_ASSERT(link) \ + if ((link)->l_info_ops != &sit_info_ops) { \ + APPBUG("Link is not a sit link. set type \"sit\" first."); \ + return -NLE_OPNOTSUPP; \ + } + +struct rtnl_link *rtnl_link_sit_alloc(void) +{ + struct rtnl_link *link; + int err; + + link = rtnl_link_alloc(); + if (!link) + return NULL; + + err = rtnl_link_set_type(link, "sit"); + if (err < 0) { + rtnl_link_put(link); + return NULL; + } + + return link; +} + +/** + * Check if link is a SIT link + * @arg link Link object + * + * @return True if link is a SIT link, otherwise false is returned. + */ +int rtnl_link_is_sit(struct rtnl_link *link) +{ + return link->l_info_ops && !strcmp(link->l_info_ops->io_name, "sit"); +} + +/** + * Create a new sit tunnel device + * @arg sock netlink socket + * @arg name name of the tunnel device + * + * Creates a new sit tunnel device in the kernel + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_add(struct nl_sock *sk, const char *name) +{ + struct rtnl_link *link; + int err; + + link = rtnl_link_sit_alloc(); + if (!link) + return -NLE_NOMEM; + + if(name) + rtnl_link_set_name(link, name); + + err = rtnl_link_add(sk, link, NLM_F_CREATE); + rtnl_link_put(link); + + return err; +} + +/** + * Set SIT tunnel interface index + * @arg link Link object + * @arg index interface index + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_link(struct rtnl_link *link, uint32_t index) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->link = index; + sit->sit_mask |= SIT_ATTR_LINK; + + return 0; +} + +/** + * Get SIT tunnel interface index + * @arg link Link object + * + * @return interface index value + */ +uint32_t rtnl_link_sit_get_link(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->link; +} + +/** + * Set SIT tunnel local address + * @arg link Link object + * @arg addr local address + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_local(struct rtnl_link *link, uint32_t addr) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->local = addr; + sit->sit_mask |= SIT_ATTR_LOCAL; + + return 0; +} + +/** + * Get SIT tunnel local address + * @arg link Link object + * + * @return local address value + */ +uint32_t rtnl_link_sit_get_local(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->local; +} + +/** + * Set SIT tunnel remote address + * @arg link Link object + * @arg remote remote address + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_remote(struct rtnl_link *link, uint32_t addr) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->remote = addr; + sit->sit_mask |= SIT_ATTR_REMOTE; + + return 0; +} + +/** + * Get SIT tunnel remote address + * @arg link Link object + * + * @return remote address + */ +uint32_t rtnl_link_sit_get_remote(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->remote; +} + +/** + * Set SIT tunnel ttl + * @arg link Link object + * @arg ttl tunnel ttl + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_ttl(struct rtnl_link *link, uint8_t ttl) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->ttl = ttl; + sit->sit_mask |= SIT_ATTR_TTL; + + return 0; +} + +/** + * Get SIT tunnel ttl + * @arg link Link object + * + * @return ttl value + */ +uint8_t rtnl_link_sit_get_ttl(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->ttl; +} + +/** + * Set SIT tunnel tos + * @arg link Link object + * @arg tos tunnel tos + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_tos(struct rtnl_link *link, uint8_t tos) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->tos = tos; + sit->sit_mask |= SIT_ATTR_TOS; + + return 0; +} + +/** + * Get SIT tunnel tos + * @arg link Link object + * + * @return tos value + */ +uint8_t rtnl_link_sit_get_tos(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->tos; +} + +/** + * Set SIT tunnel path MTU discovery + * @arg link Link object + * @arg pmtudisc path MTU discovery + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_pmtudisc(struct rtnl_link *link, uint8_t pmtudisc) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->pmtudisc = pmtudisc; + sit->sit_mask |= SIT_ATTR_PMTUDISC; + + return 0; +} + +/** + * Get SIT path MTU discovery + * @arg link Link object + * + * @return pmtudisc value + */ +uint8_t rtnl_link_sit_get_pmtudisc(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->pmtudisc; +} + +/** + * Set SIT tunnel flags + * @arg link Link object + * @arg flags tunnel flags + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_flags(struct rtnl_link *link, uint16_t flags) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->flags = flags; + sit->sit_mask |= SIT_ATTR_FLAGS; + + return 0; +} + +/** + * Get SIT path flags + * @arg link Link object + * + * @return flags value + */ +uint16_t rtnl_link_sit_get_flags(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->flags; +} + +/** + * Set SIT tunnel proto + * @arg link Link object + * @arg proto tunnel proto + * + * @return 0 on success or a negative error code + */ +int rtnl_link_sit_set_proto(struct rtnl_link *link, uint8_t proto) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + sit->proto = proto; + sit->sit_mask |= SIT_ATTR_PROTO; + + return 0; +} + +/** + * Get SIT proto + * @arg link Link object + * + * @return proto value + */ +uint8_t rtnl_link_sit_get_proto(struct rtnl_link *link) +{ + struct sit_info *sit = link->l_info; + + IS_SIT_LINK_ASSERT(link); + + return sit->proto; +} + +static void __init sit_init(void) +{ + rtnl_link_register_info(&sit_info_ops); +} + +static void __exit sit_exit(void) +{ + rtnl_link_unregister_info(&sit_info_ops); +} diff --git a/tests/.gitignore b/tests/.gitignore index edb8a83..f7409c6 100644 --- a/tests/.gitignore +++ b/tests/.gitignore @@ -9,6 +9,7 @@ /test-create-bridge /test-create-ipgre /test-create-ipip +/test-create-sit /test-create-veth /test-create-vlan /test-create-vxlan diff --git a/tests/Makefile.am b/tests/Makefile.am index 5bc939e..584ab60 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -26,6 +26,7 @@ check_PROGRAMS = \ test-create-bridge \ test-create-ipgre \ test-create-ipip \ + test-create-sit \ test-delete-link \ test-socket-creation \ test-complex-HTB-with-hash-filters \ diff --git a/tests/test-create-sit.c b/tests/test-create-sit.c new file mode 100644 index 0000000..d33e496 --- /dev/null +++ b/tests/test-create-sit.c @@ -0,0 +1,56 @@ +#include +#include + +int main(int argc, char *argv[]) +{ + struct nl_cache *link_cache; + struct rtnl_link *link; + struct in_addr addr; + struct nl_sock *sk; + int err, if_index; + + sk = nl_socket_alloc(); + if ((err = nl_connect(sk, NETLINK_ROUTE)) < 0) { + nl_perror(err, "Unable to connect socket"); + return err; + } + + err = rtnl_link_alloc_cache(sk, AF_UNSPEC, &link_cache); + if ( err < 0) { + nl_perror(err, "Unable to allocate cache"); + return err; + } + + if_index = rtnl_link_name2i(link_cache, "eno16777736"); + if (!if_index) { + fprintf(stderr, "Unable to lookup eno16777736"); + return -1; + } + + link = rtnl_link_sit_alloc(); + if(!link) { + nl_perror(err, "Unable to allocate link"); + return -1; + + } + rtnl_link_set_name(link, "sit-tun"); + rtnl_link_sit_set_link(link, if_index); + + inet_pton(AF_INET, "192.168.254.12", &addr.s_addr); + rtnl_link_sit_set_local(link, addr.s_addr); + + inet_pton(AF_INET, "192.168.254.13", &addr.s_addr); + rtnl_link_sit_set_remote(link, addr.s_addr); + + rtnl_link_sit_set_ttl(link, 64); + err = rtnl_link_add(sk, link, NLM_F_CREATE); + if (err < 0) { + nl_perror(err, "Unable to add link"); + return err; + } + + rtnl_link_put(link); + nl_close(sk); + + return 0; +}