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Diffstat (limited to 'src/net/packets.hpp')
-rw-r--r-- | src/net/packets.hpp | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/src/net/packets.hpp b/src/net/packets.hpp new file mode 100644 index 0000000..2e3d77c --- /dev/null +++ b/src/net/packets.hpp @@ -0,0 +1,354 @@ +#ifndef TMWA_NET_PACKETS_HPP +#define TMWA_NET_PACKETS_HPP +// packets.hpp - palatable socket buffer accessors +// +// Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com> +// +// This file is part of The Mana World (Athena server) +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. + +# include "fwd.hpp" + +# include "../compat/cast.hpp" + +# include "../ints/little.hpp" + + #include "../io/fwd.hpp" + +# include "socket.hpp" + +enum class RecvResult +{ + Incomplete, + Complete, + Error, +}; + +enum class SendResult +{ + Success, + Fail, +}; + + +size_t packet_avail(Session *s); +void packet_dump(io::WriteFile& out, Session *s); + +bool packet_fetch(Session *s, size_t offset, Byte *data, size_t sz); +void packet_discard(Session *s, size_t sz); +bool packet_send(Session *s, const Byte *data, size_t sz); + +inline +bool packet_peek_id(Session *s, uint16_t *packet_id) +{ + Little16 id; + bool okay = packet_fetch(s, 0, reinterpret_cast<Byte *>(&id), 2); + if (okay) + { + if (!network_to_native(packet_id, id)) + { + s->set_eof(); + return false; + } + } + return okay; +} + +template<class F> +__attribute__((warn_unused_result)) +SendResult net_send_fpacket(Session *s, const F& fixed) +{ + bool ok = packet_send(s, reinterpret_cast<const Byte *>(&fixed), sizeof(F)); + return ok ? SendResult::Success : SendResult::Fail; +} + +template<class H, class R> +__attribute__((warn_unused_result)) +SendResult net_send_vpacket(Session *s, const H& head, const std::vector<R>& repeat) +{ + bool ok = packet_send(s, reinterpret_cast<const Byte *>(&head), sizeof(H)); + ok &= packet_send(s, reinterpret_cast<const Byte *>(repeat.data()), repeat.size() * sizeof(R)); + return ok ? SendResult::Success : SendResult::Fail; +} + +template<class F> +__attribute__((warn_unused_result)) +RecvResult net_recv_fpacket(Session *s, F& fixed) +{ + bool ok = packet_fetch(s, 0, reinterpret_cast<Byte *>(&fixed), sizeof(F)); + if (ok) + { + packet_discard(s, sizeof(F)); + return RecvResult::Complete; + } + return RecvResult::Incomplete; +} + +template<class HNat, class H, class R> +__attribute__((warn_unused_result)) +RecvResult net_recv_vpacket(Session *s, H& head, std::vector<R>& repeat) +{ + bool ok = packet_fetch(s, 0, reinterpret_cast<Byte *>(&head), sizeof(H)); + if (ok) + { + HNat nat; + if (!network_to_native(&nat, head)) + return RecvResult::Error; + if (packet_avail(s) < nat.magic_packet_length) + return RecvResult::Incomplete; + if (nat.magic_packet_length < sizeof(H)) + return RecvResult::Error; + size_t bytes_repeat = nat.magic_packet_length - sizeof(H); + if (bytes_repeat % sizeof(R)) + return RecvResult::Error; + repeat.resize(bytes_repeat / sizeof(R)); + if (packet_fetch(s, sizeof(H), reinterpret_cast<Byte *>(repeat.data()), bytes_repeat)) + { + packet_discard(s, nat.magic_packet_length); + return RecvResult::Complete; + } + return RecvResult::Incomplete; + } + return RecvResult::Incomplete; +} + + +template<uint16_t id, uint16_t size, class F> +void send_fpacket(Session *s, const F& fixed) +{ + static_assert(id == F::PACKET_ID, "F::PACKET_ID"); + static_assert(size == sizeof(typename F::NetType), "F::NetType"); + + typename F::NetType net_fixed; + if (!native_to_network(&net_fixed, fixed)) + { + s->set_eof(); + return; + } + SendResult rv = net_send_fpacket(s, net_fixed); + if (rv != SendResult::Success) + s->set_eof(); +} + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class H, class R> +void send_vpacket(Session *s, H& head, const std::vector<R>& repeat) +{ + static_assert(id == H::PACKET_ID, "H::PACKET_ID"); + static_assert(headsize == sizeof(typename H::NetType), "H::NetType"); + static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == sizeof(typename R::NetType), "R::NetType"); + + typename H::NetType net_head; + // since these are already allocated, can't overflow address space + size_t total_size = sizeof(typename H::NetType) + repeat.size() * sizeof(typename R::NetType); + // truncates + head.magic_packet_length = total_size; + if (head.magic_packet_length != total_size) + { + s->set_eof(); + return; + } + // TODO potentially avoid the allocation + std::vector<typename R::NetType> net_repeat(repeat.size()); + if (!native_to_network(&net_head, head)) + { + s->set_eof(); + return; + } + for (size_t i = 0; i < repeat.size(); ++i) + { + if (!native_to_network(&net_repeat[i], repeat[i])) + { + s->set_eof(); + return; + } + } + SendResult rv = net_send_vpacket(s, net_head, net_repeat); + if (rv != SendResult::Success) + s->set_eof(); +} + +template<uint16_t id, uint16_t size, class F> +__attribute__((warn_unused_result)) +RecvResult recv_fpacket(Session *s, F& fixed) +{ + static_assert(id == F::PACKET_ID, "F::PACKET_ID"); + static_assert(size == sizeof(typename F::NetType), "F::NetType"); + + typename F::NetType net_fixed; + RecvResult rv = net_recv_fpacket(s, net_fixed); + assert (fixed.magic_packet_id == F::PACKET_ID); + if (rv == RecvResult::Complete) + { + if (!network_to_native(&fixed, net_fixed)) + return RecvResult::Error; + } + return rv; +} + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class H, class R> +__attribute__((warn_unused_result)) +RecvResult recv_vpacket(Session *s, H& head, std::vector<R>& repeat) +{ + static_assert(id == H::PACKET_ID, "H::PACKET_ID"); + static_assert(headsize == sizeof(typename H::NetType), "H::NetType"); + static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == sizeof(typename R::NetType), "R::NetType"); + + typename H::NetType net_head; + std::vector<typename R::NetType> net_repeat; + RecvResult rv = net_recv_vpacket<H>(s, net_head, net_repeat); + assert (head.magic_packet_id == H::PACKET_ID); + if (rv == RecvResult::Complete) + { + if (!network_to_native(&head, net_head)) + return RecvResult::Error; + repeat.resize(net_repeat.size()); + for (size_t i = 0; i < net_repeat.size(); ++i) + { + if (!network_to_native(&repeat[i], net_repeat[i])) + return RecvResult::Error; + } + } + return rv; +} + +// convenience for trailing strings + +struct VarStringNetType +{ + char c; +}; + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class H> +void send_vpacket(Session *s, H& head, const XString& repeat) +{ + static_assert(id == H::PACKET_ID, "H::PACKET_ID"); + static_assert(headsize == sizeof(typename H::NetType), "H::NetType"); + // static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == 1, "R::NetType"); + + typename H::NetType net_head; + // since it's already allocated, it can't overflow address space + size_t total_length = sizeof(typename H::NetType) + (repeat.size() + 1) * sizeof(VarStringNetType); + head.magic_packet_length = total_length; + if (head.magic_packet_length != total_length) + { + s->set_eof(); + return; + } + // TODO potentially avoid the allocation + std::vector<VarStringNetType> net_repeat(repeat.size() + 1); + if (!native_to_network(&net_head, head)) + { + s->set_eof(); + return; + } + for (size_t i = 0; i < repeat.size(); ++i) + { + net_repeat[i].c = repeat[i]; + } + net_repeat[repeat.size()].c = '\0'; + SendResult rv = net_send_vpacket(s, net_head, net_repeat); + if (rv != SendResult::Success) + s->set_eof(); +} + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class H> +__attribute__((warn_unused_result)) +RecvResult recv_vpacket(Session *s, H& head, AString& repeat) +{ + static_assert(id == H::PACKET_ID, "H::PACKET_ID"); + static_assert(headsize == sizeof(typename H::NetType), "H::NetType"); + //static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == 1, "R::NetType"); + + typename H::NetType net_head; + std::vector<VarStringNetType> net_repeat; + RecvResult rv = net_recv_vpacket<H>(s, net_head, net_repeat); + assert (head.magic_packet_id == H::PACKET_ID); + if (rv == RecvResult::Complete) + { + if (!network_to_native(&head, net_head)) + return RecvResult::Error; + // reinterpret_cast is needed to correctly handle an empty vector + const char *begin = sign_cast<const char *>(net_repeat.data()); + const char *end = begin + repeat.size(); + end = std::find(begin, end, '\0'); + repeat = XString(begin, end, nullptr); + } + return rv; +} + + +// if there is nothing in the head but the id and length, use the below + +// TODO make this go away with template specialization + +template<uint16_t PKT_ID> +struct NetCommonPacketHead +{ + Little16 magic_packet_id; + Little16 magic_packet_length; +}; + +template<uint16_t PKT_ID> +struct CommonPacketHead +{ + using NetType = NetCommonPacketHead<PKT_ID>; + static const uint16_t PACKET_ID = PKT_ID; + + uint16_t magic_packet_id = PACKET_ID; + uint16_t magic_packet_length; +}; + +template<uint16_t PKT_ID> +bool native_to_network(NetCommonPacketHead<PKT_ID> *net, CommonPacketHead<PKT_ID> nat) +{ + return native_to_network(&net->magic_packet_id, nat.magic_packet_id) + && native_to_network(&net->magic_packet_length, nat.magic_packet_length); +} + +template<uint16_t PKT_ID> +bool network_to_native(CommonPacketHead<PKT_ID> *nat, NetCommonPacketHead<PKT_ID> net) +{ + return network_to_native(&nat->magic_packet_id, net.magic_packet_id) + && network_to_native(&nat->magic_packet_length, net.magic_packet_length); +} + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class R> +void send_packet_repeatonly(Session *s, const std::vector<R>& v) +{ + static_assert(headsize == 4, "repeat headsize"); + static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == sizeof(typename R::NetType), "R::NetType"); + + CommonPacketHead<R::PACKET_ID> head; + send_vpacket<id, 4, repeatsize>(s, head, v); +} + +template<uint16_t id, uint16_t headsize, uint16_t repeatsize, class R> +__attribute__((warn_unused_result)) +RecvResult recv_packet_repeatonly(Session *s, std::vector<R>& v) +{ + static_assert(headsize == 4, "repeat headsize"); + static_assert(id == R::PACKET_ID, "R::PACKET_ID"); + static_assert(repeatsize == sizeof(typename R::NetType), "R::NetType"); + + CommonPacketHead<R::PACKET_ID> head; + return recv_vpacket<id, 4, repeatsize>(s, head, v); +} + +#endif // TMWA_NET_PACKETS_HPP |