C++ api client
This describes how to write a C++ api client connecting to VPP’s binary API.
Connecting to VPP is done with :
auto err = con.connect("example_client", nullptr, 32, 32);
You can specify the path to the api socket/shared memory you want to connect to
with the second parameter (set to nullptr, meaning default)
//
// VPP C++ API example
//
// The uplink is the 1st interface (sw_if_index is 1) and is set
// to 10.10.10.10/24 The uplink gateway is 10.10.10.1 The IPsec tunnel is set
// between 10.10.10.10 and 10.20.20.20 The protected subnet is 192.168.0.0/24
// VRF 1 is for uplink ingress
// VRF 2 is IPsec egress (clear -> cipher)
// VRF 3 is IPsec ingress (cipher -> clear)
//
// The following examples must be run with VPP in the following state:
// ip table add 1 # VRF 1
// ip table add 2 # VRF 2
// ip table add 3 # VRF 3
// loop create # loop0 is used as uplink with sw_if_index=1
// set int ip table loop0 1 # VRF 1 is ingress
// set int state loop0 up
//
// Then the API will configure VPP similar to this:
// # configure uplink address
// set int addr loop0 10.10.10.10/24
// # create the IP-IP tunnel
// create ipip tunnel src 10.10.10.1 dst 10.20.20.20 outer-table-id 2
// # use VRF-3 as IPsec ingress VRF (cipher -> clear)
// set int ip table ipip0 3
// set int unnum ipip0 use loop0
// set int state ipip0 up
// ipsec sa add 20 spi 200 crypto-key 01234567890123456789012345678901
// crypto-alg aes-cbc-128 integ-key 01234567890123456789 integ-alg sha1-96
// use-anti-replay udp-encap
// ipsec sa add 30 spi 300 crypto-key 01234567890123456789012345678901
// crypto-alg aes-cbc-128 integ-key 01234567890123456789 integ-alg sha1-96
// use-anti-replay udp-encap
// # protect IP-IP with IPsec
// ipsec tunnel protect ipip0 sa-in 30 sa-out 20
// # subnet to route through IPsec (clear -> cipher)
// ip route add table 1 192.168.0.0/24 via ipip0
// # default route for IPsec packets after encapsulation (clear -> cipher)
// ip route add table 20.0.0.0/0 via 10.10.10.1 loop0
// # default route for clear-text packets after decapsulation
// # (cipher -> clear)
// ip route add table 30.0.0.0/0 via 10.10.10.1 loop0
//
#include <iostream>
#include <algorithm>
#include <vapi/vapi.hpp>
#include <vapi/vpe.api.vapi.hpp>
DEFINE_VAPI_MSG_IDS_VPE_API_JSON
#include <vapi/interface.api.vapi.hpp>
DEFINE_VAPI_MSG_IDS_INTERFACE_API_JSON
#include <vapi/ip.api.vapi.hpp>
DEFINE_VAPI_MSG_IDS_IP_API_JSON
#include <vapi/ipip.api.vapi.hpp>
DEFINE_VAPI_MSG_IDS_IPIP_API_JSON
#include <vapi/ipsec.api.vapi.hpp>
DEFINE_VAPI_MSG_IDS_IPSEC_API_JSON
template <typename MyRequest>
static auto &
execute (vapi::Connection &con, MyRequest &req)
{
// send the command to VPP
auto err = req.execute ();
if (VAPI_OK != err)
throw std::runtime_error ("execute()");
// active-wait for command result
do
{
err = con.wait_for_response (req);
}
while (VAPI_EAGAIN == err);
if (VAPI_OK != err)
throw std::runtime_error ("wait_for_response()");
// verify the reply error code
auto &rmp = req.get_response ().get_payload ();
if (0 != rmp.retval)
throw std::runtime_error ("wrong return code");
return rmp;
}
static void
route_add (vapi::Connection &con, const int vrf, const unsigned char prefix[4],
const int plen, const int sw_if_index, const unsigned char nh[4])
{
std::cout << "Adding route..." << std::endl;
// ip route add table <vrf> <prefix>/<plen> via <nh> <sw_if_index>
vapi::Ip_route_add_del route (con,
1); // cf. src/vnet/ip/ip.api:ip_route_add_del
// - we allocate space for 1 path (nh)
auto &mp = route.get_request ().get_payload ();
mp.is_add = true;
mp.is_multipath = false;
mp.route.table_id = vrf;
mp.route.prefix.address.af = ADDRESS_IP4;
std::copy (prefix, prefix + 4, mp.route.prefix.address.un.ip4);
mp.route.prefix.len = plen;
mp.route.n_paths =
1; // 1 path, must match allocation in route declaration above
// cf. src/vnet/fib/fib_types.api:fib_path
mp.route.paths[0].sw_if_index = sw_if_index;
mp.route.paths[0].proto = FIB_API_PATH_NH_PROTO_IP4;
std::copy (nh, nh + 4, mp.route.paths[0].nh.address.ip4);
execute (con, route);
}
static void
ipsec_sa_add (vapi::Connection &con, const int id, const int spi)
{
std::cout << "Adding SA " << id << "..." << std::endl;
// ipsec sa add <id> spi <spi> crypto-key 01234567890123456789012345678901
// crypto-alg aes-cbc-128 integ-key 01234567890123456789 integ-alg sha1-96
// use-anti-replay udp-encap
vapi::Ipsec_sad_entry_add_del_v2 ipsec (
con); // cf. src/vnet/ipsec/ipsec.api:ipsec_sad_entry_add_del_v2
auto &mp = ipsec.get_request ().get_payload ();
mp.is_add = true;
// cf. src/vnet/ipsec/ipsec_types.api:ipsec_sad_entry_v2
mp.entry.sad_id = id; // user-defined SA id
mp.entry.spi = spi;
mp.entry.protocol = IPSEC_API_PROTO_ESP;
mp.entry.crypto_algorithm = IPSEC_API_CRYPTO_ALG_AES_CBC_128;
const char key[] =
"\x01\x23\x45\x67\x89\x01\x23\x45\x67\x89\x01\x23\x45\x67\x89\x01";
// cf. src/vnet/ipsec/ipsec_types.api:key
mp.entry.crypto_key.length = sizeof (key) - 1;
std::copy (key, key + sizeof (key) - 1, mp.entry.crypto_key.data);
mp.entry.integrity_algorithm = IPSEC_API_INTEG_ALG_SHA1_96;
mp.entry.integrity_key.length = sizeof (key) - 1;
std::copy (key, key + sizeof (key) - 1, mp.entry.integrity_key.data);
mp.entry.flags = (vapi_enum_ipsec_sad_flags) (
IPSEC_API_SAD_FLAG_USE_ANTI_REPLAY | IPSEC_API_SAD_FLAG_UDP_ENCAP);
mp.entry.udp_src_port = 4500;
mp.entry.udp_dst_port = 4500;
execute (con, ipsec);
}
int
main ()
{
// Connect to VPP: client name, API prefix, max outstanding request, response
// queue size
std::cout << "Connecting to VPP..." << std::endl;
vapi::Connection con;
auto err = con.connect ("example_client", nullptr, 32, 32);
if (VAPI_OK != err)
throw std::runtime_error ("connection to VPP failed");
try
{
std::cout << "Configuring address..." << std::endl;
{
// set int addr <uplink> 10.10.10.10/24
vapi::Sw_interface_add_del_address addr (
con); // cf. src/vnet/interface.api:sw_interface_add_del_address
auto &mp = addr.get_request ().get_payload ();
mp.sw_if_index = 1; // uplink
mp.is_add = true;
mp.prefix.address.af = ADDRESS_IP4;
const char ip[] = { 0x0a, 0x0a, 0x0a, 0x0a }; // 10.10.10.10
std::copy (ip, ip + 4, mp.prefix.address.un.ip4);
mp.prefix.len = 24;
execute (con, addr);
}
std::cout << "Creating IP-IP tunnel..." << std::endl;
unsigned ipip_sw_if_index;
{
// create ipip tunnel src 10.10.10.1 dst 10.20.20.20 outer-table-id 2
vapi::Ipip_add_tunnel ipip (
con); // cf. src/vnet/ipip/ipip.api:ipip_add_tunnel
auto &mp = ipip.get_request ().get_payload ();
mp.tunnel.instance = ~0;
mp.tunnel.src.af = ADDRESS_IP4;
const char src[] = { 0x0a, 0x0a, 0x0a, 0x0a }; // 10.10.10.10
std::copy (src, src + 4, mp.tunnel.src.un.ip4);
mp.tunnel.dst.af = ADDRESS_IP4;
const char dst[] = { 0x0a, 0x14, 0x14, 0x14 }; // 10.20.20.20
std::copy (dst, dst + 4, mp.tunnel.dst.un.ip4);
mp.tunnel.table_id =
2; // VRF 2 - encapsulated (ciphered) packets should be lookup'ed in
// VRF 2 to determine path
auto &rmp = execute (con, ipip);
ipip_sw_if_index =
rmp.sw_if_index; // save ipip tunnel index for later use
}
std::cout << "Moving IP-IP tunnel to VRF 3..." << std::endl;
{
// set int ip table ipip0 3
vapi::Sw_interface_set_table table (
con); // cf. src/vnet/interface.api:sw_interface_set_table
auto &mp = table.get_request ().get_payload ();
mp.sw_if_index = ipip_sw_if_index;
mp.vrf_id = 3; // VRF 3 - decapsulated (deciphered) packets should be
// lookup'ed in VRF 3 to determine path
execute (con, table);
}
std::cout << "Configuring IP-IP tunnel as unnumbered..." << std::endl;
{
// set int unnum ipip0 use <uplink>
vapi::Sw_interface_set_unnumbered unnum (
con); // cf. src/vnet/interface.api:sw_interface_set_unnumbered
auto &mp = unnum.get_request ().get_payload ();
mp.sw_if_index = 1; // uplink
mp.unnumbered_sw_if_index = ipip_sw_if_index;
execute (con, unnum);
}
std::cout << "Setting IP-IP tunnel up..." << std::endl;
{
// set int state ipip0 up
vapi::Sw_interface_set_flags flags (
con); // cf. src/vnet/interface.api:sw_interface_set_flags
auto &mp = flags.get_request ().get_payload ();
mp.sw_if_index = ipip_sw_if_index;
mp.flags = IF_STATUS_API_FLAG_ADMIN_UP;
execute (con, flags);
}
// ipsec sa add 20 spi 200 crypto-key 01234567890123456789012345678901
// crypto-alg aes-cbc-128 integ-key 01234567890123456789 integ-alg
// sha1-96 use-anti-replay udp-encap
ipsec_sa_add (con, 20, 200);
// ipsec sa add 30 spi 300 crypto-key 01234567890123456789012345678901
// crypto-alg aes-cbc-128 integ-key 01234567890123456789 integ-alg
// sha1-96 use-anti-replay udp-encap
ipsec_sa_add (con, 30, 300);
std::cout << "Protecting IP-IP tunnel..." << std::endl;
{
// ipsec tunnel protect ipip0 sa-in 30 sa-out 20
vapi::Ipsec_tunnel_protect_update tun (
con, 1); // cf. src/vnet/ipsec/ipsec.api:ipsec_tunnel_protect_update
// - we allocate space for 1 sa_in
auto &mp = tun.get_request ().get_payload ();
// cf. src/vnet/ipsec/ipsec.api:ipsec_tunnel_protect
mp.tunnel.sw_if_index = ipip_sw_if_index;
mp.tunnel.sa_out = 20;
mp.tunnel.n_sa_in =
1; // 1 SA, must match allocation in declaration above
mp.tunnel.sa_in[0] = 30;
execute (con, tun);
}
// add route for clear-text packets to be encrypted
// ip route add table 1 192.168.0.0/24 via ipip0
route_add (con,
1, // VRF 1
(const unsigned char[]){ 192, 168, 0, 0 },
24, // 192.168.0.0/24
ipip_sw_if_index, // ipip0
(const unsigned char[]){}); // 0
// add default route for encrypted packets (clear -> ciphered)
// ip route add table 2 0.0.0.0/0 via 10.10.10.1 <uplink>
route_add (con,
2, // VRF 2
(const unsigned char[]){}, 0, // 0.0.0.0/0
1, // <uplink>
(const unsigned char[]){ 10, 10, 10, 1 }); // 10.0.0.1
// add default route for decrypted packets (ciphered -> clear)
// ip route add table 3 0.0.0.0/0 via 10.10.10.1 <uplink>
route_add (con,
3, // VRF 3
(const unsigned char[]){}, 0, // 0.0.0.0/0
1, // <uplink>
(const unsigned char[]){ 10, 10, 10, 1 }); // 10.0.0.1
}
catch (...)
{
std::cerr << "Failure" << std::endl;
con.disconnect ();
return 1;
}
con.disconnect ();
std::cerr << "Success" << std::endl;
return 0;
}
To build this you could use the following makefile
CXXFLAGS:=-std=c++14 -Wextra -Wall -g -O2
CXXFLAGS+= -Wno-unused-parameter
#CXXFLAGS+= -O0
LDFLAGS:=-g
LDLIBS:=-lvapiclient
# Customize the lines below if VPP headers and libraries are in non-standard paths
#CXXFLAGS+= -I/your/vpp/build-root/install-vpp_debug-native/vpp/include
#LDFLAGS+= -Wl,-rpath,/your/vpp/build-root/install-vpp_debug-native/vpp/lib
#LDFLAGS+= -L/your/vpp/build-root/install-vpp_debug-native/vpp/lib
all: api_example
clean:
$(RM) api_example
.PHONY: all clean