Commit edd0b062 authored by Marcin Siodelski's avatar Marcin Siodelski
Browse files

[2902] Moved protocol utility functions to a separate file.

parent 45e29ee0
......@@ -33,6 +33,7 @@ libb10_dhcp___la_SOURCES += option_custom.cc option_custom.h
libb10_dhcp___la_SOURCES += option_data_types.cc option_data_types.h
libb10_dhcp___la_SOURCES += option_definition.cc option_definition.h
libb10_dhcp___la_SOURCES += option_space.cc option_space.h
libb10_dhcp___la_SOURCES += protocol_util.cc protocol_util.h
libb10_dhcp___la_SOURCES += pkt6.cc pkt6.h
libb10_dhcp___la_SOURCES += pkt4.cc pkt4.h
libb10_dhcp___la_SOURCES += pkt_filter.h
......
......@@ -16,94 +16,17 @@
#include <dhcp/iface_mgr.h>
#include <dhcp/pkt4.h>
#include <dhcp/pkt_filter_lpf.h>
#include <dhcp/protocol_util.h>
#include <exceptions/exceptions.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
using namespace isc::util;
namespace isc {
namespace dhcp {
void
PktFilterLPF::assembleEthernetHeader(const Iface& iface,
const Pkt4Ptr& pkt,
util::OutputBuffer& out_buf) {
std::vector<uint8_t> dest_addr = pkt->getHWAddr()->hwaddr_;
if (dest_addr.empty()) {
dest_addr.resize(HWAddr::ETHERNET_HWADDR_LEN);
}
out_buf.writeData(&dest_addr[0], dest_addr.size());
out_buf.writeData(iface.getMac(), iface.getMacLen());
out_buf.writeUint16(0x0800);
}
void
PktFilterLPF::assembleIpUdpHeader(const Pkt4Ptr& pkt,
util::OutputBuffer& out_buf) {
struct ip ip_hdr;
memset(&ip_hdr, 0, sizeof(ip_hdr));
ip_hdr.ip_hl = (ip_hdr.ip_hl | 5) & 0xF;
ip_hdr.ip_v = (ip_hdr.ip_v | 4) & 0xF;
ip_hdr.ip_tos = IPTOS_LOWDELAY;
ip_hdr.ip_len = htons(sizeof(ip) + sizeof(udphdr) +
pkt->getBuffer().getLength());
ip_hdr.ip_id = 0;
ip_hdr.ip_off = 0;
ip_hdr.ip_ttl = 128;
ip_hdr.ip_p = IPPROTO_UDP;
ip_hdr.ip_src.s_addr = htonl(pkt->getLocalAddr());
ip_hdr.ip_dst.s_addr = htonl(pkt->getRemoteAddr());
ip_hdr.ip_sum = checksumFinish(checksum(reinterpret_cast<const char*>(&ip_hdr),
sizeof(ip_hdr)));
out_buf.writeData(static_cast<void*>(&ip_hdr), sizeof(ip_hdr));
struct udphdr udp_hdr;
memset(&udp_hdr, 0, sizeof(udp_hdr));
udp_hdr.source = htons(pkt->getLocalPort());
udp_hdr.dest = htons(pkt->getRemotePort());
udp_hdr.len = htons(sizeof(udp_hdr) + pkt->getBuffer().getLength());
udp_hdr.check = 0;
out_buf.writeData(static_cast<void*>(&udp_hdr), sizeof(udp_hdr));
}
uint16_t
PktFilterLPF::checksum(const char* buf, const uint32_t buf_size,
uint32_t sum) {
uint32_t i;
for (i = 0; i < (buf_size & ~1U); i += 2) {
uint16_t chunk = buf[i] << 8 | buf[i+1];
sum += chunk;
if (sum > 0xFFFF) {
sum -= 0xFFFF;
}
}
if (i < buf_size) {
sum += buf[i] << 8;
if (sum > 0xFFFF) {
sum -= 0xFFFF;
}
}
return (sum);
}
uint16_t
PktFilterLPF::checksumFinish(uint16_t sum) {
return (htons(~sum));
}
int
PktFilterLPF::openSocket(const Iface& iface, const isc::asiolink::IOAddress&,
const uint16_t, const bool,
......@@ -131,9 +54,19 @@ PktFilterLPF::openSocket(const Iface& iface, const isc::asiolink::IOAddress&,
}
Pkt4Ptr
PktFilterLPF::receive(const Iface&, const SocketInfo&) {
isc_throw(isc::NotImplemented,
"Linux Packet Filtering is not implemented yet");
PktFilterLPF::receive(const Iface&, const SocketInfo& socket_info) {
// @todo: implement this function
unsigned char buf[1536];
int data_len = read(socket_info.sockfd_, buf, sizeof(buf));
if (data_len <= 0) {
return Pkt4Ptr();
}
// Length of the Ethernet, IP and UDP.
int data_offset = 42;
Pkt4Ptr pkt = Pkt4Ptr(new Pkt4(buf + data_offset,
data_len - data_offset));
return (pkt);
}
int
......@@ -141,9 +74,17 @@ PktFilterLPF::send(const Iface& iface, uint16_t sockfd, const Pkt4Ptr& pkt) {
OutputBuffer buf(14);
assembleEthernetHeader(iface, pkt, buf);
assembleIpUdpHeader(pkt, buf);
// Ethernet frame header
std::vector<uint8_t> dest_addr = pkt->getHWAddr()->hwaddr_;
if (dest_addr.empty()) {
dest_addr.resize(HWAddr::ETHERNET_HWADDR_LEN);
}
writeEthernetHeader(iface.getMac(), &dest_addr[0], buf);
// IP and UDP header
writeIpUdpHeader(pkt, buf);
// DHCPv4 message
buf.writeData(pkt->getBuffer().getData(), pkt->getBuffer().getLength());
sockaddr_ll sa;
......
// Copyright (C) 2013 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
#include <protocol_util.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
namespace isc {
namespace dhcp {
void
writeEthernetHeader(const uint8_t* src_hw_addr, const uint8_t* dest_hw_addr,
util::OutputBuffer& out_buf) {
// Write destination and source address.
out_buf.writeData(dest_hw_addr, HWAddr::ETHERNET_HWADDR_LEN);
out_buf.writeData(src_hw_addr, HWAddr::ETHERNET_HWADDR_LEN);
// Type IP.
out_buf.writeUint16(0x0800);
}
void
writeIpUdpHeader(const Pkt4Ptr& pkt, util::OutputBuffer& out_buf) {
struct ip ip_hdr;
memset(&ip_hdr, 0, sizeof(ip_hdr));
ip_hdr.ip_hl = (ip_hdr.ip_hl | 5) & 0xF;
ip_hdr.ip_v = (ip_hdr.ip_v | 4) & 0xF;
ip_hdr.ip_tos = IPTOS_LOWDELAY;
ip_hdr.ip_len = htons(sizeof(ip) + sizeof(udphdr) +
pkt->getBuffer().getLength());
ip_hdr.ip_id = 0;
ip_hdr.ip_off = 0;
ip_hdr.ip_ttl = 128;
ip_hdr.ip_p = IPPROTO_UDP;
ip_hdr.ip_src.s_addr = htonl(pkt->getLocalAddr());
ip_hdr.ip_dst.s_addr = htonl(pkt->getRemoteAddr());
ip_hdr.ip_sum =
wrapChecksum(calculateChecksum(reinterpret_cast<const char*>(&ip_hdr),
sizeof(ip_hdr)));
out_buf.writeData(static_cast<void*>(&ip_hdr), sizeof(ip_hdr));
struct udphdr udp_hdr;
memset(&udp_hdr, 0, sizeof(udp_hdr));
udp_hdr.source = htons(pkt->getLocalPort());
udp_hdr.dest = htons(pkt->getRemotePort());
udp_hdr.len = htons(sizeof(udp_hdr) + pkt->getBuffer().getLength());
udp_hdr.check = 0;
out_buf.writeData(static_cast<void*>(&udp_hdr), sizeof(udp_hdr));
}
uint16_t
calculateChecksum(const char* buf, const uint32_t buf_size, uint32_t sum) {
uint32_t i;
for (i = 0; i < (buf_size & ~1U); i += 2) {
uint16_t chunk = buf[i] << 8 | buf[i+1];
sum += chunk;
if (sum > 0xFFFF) {
sum -= 0xFFFF;
}
}
if (i < buf_size) {
sum += buf[i] << 8;
if (sum > 0xFFFF) {
sum -= 0xFFFF;
}
}
return (sum);
}
uint16_t
wrapChecksum(uint16_t sum) {
return (htons(~sum));
}
}
}
// Copyright (C) 2013 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
#ifndef PROTOCOL_UTIL_H
#define PROTOCOL_UTIL_H
#include <dhcp/pkt4.h>
#include <util/buffer.h>
#include <stdint.h>
namespace isc {
namespace dhcp {
/// @brief Writes ethernet frame header into a buffer.
///
/// @param src_hw_addr source HW address.
/// @param dst_hw_addr destination HW address.
/// @param [out] out_buf buffer where a header is written.
void writeEthernetHeader(const uint8_t* src_hw_addr,
const uint8_t* dest_hw_addr,
util::OutputBuffer& out_buf);
/// @brief Writes both IP and UDP header into output buffer
///
/// This utility function assembles IP and UDP packet headers for the
/// provided DHCPv4 message. The source and destination addreses and
/// ports stored in the Pkt4 object are copied as source and destination
/// addresses and ports into IP/UDP headers.
///
/// @param pkt DHCPv4 packet to be sent in IP packet
/// @param [out] out_buf buffer where an IP header is written
void writeIpUdpHeader(const Pkt4Ptr& pkt, util::OutputBuffer& out_buf);
/// @brief Calculates checksum for provided buffer
///
/// @param buf buffer for which the checksum is calculated.
/// @param buf_size size of the buffer for which checksum is calculated.
/// @param sum initial checksum value.
///
/// @return calculated checksum.
uint16_t calculateChecksum(const char* buf, const uint32_t buf_size,
uint32_t sum = 0);
/// @brief Wraps the calculated checksum and stores it in network byte order.
///
/// @param sum calculated checksum
///
/// @return wrapped checksum value.
uint16_t wrapChecksum(uint16_t sum);
}
}
#endif // PROTOCOL_UTIL_H
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment