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/* Copyright 2016 The Roughtime Authors.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License. */
#include <arpa/inet.h>
#include <netinet/in.h>
#include <memory>
#include <vector>
#include "server.h"
namespace roughtime {
#if defined(__MACH__) || defined(__Fuchsia__)
struct mmsghdr {
uint8_t *iov_base;
size_t msg_len;
msghdr msg_hdr;
// UdpProcessor manages a set of receive buffers for processing UDP requests.
class UdpProcessor {
// Stats contains various counters for a single batch.
struct Stats {
size_t bytes_in;
size_t bytes_out;
unsigned packets_in;
unsigned packets_out;
unsigned requests_invalid;
unsigned requests_truncated;
virtual ~UdpProcessor();
// AddBrokenReplyGenerator adds a BrokenReplyGenerator that will be used for
// a fraction of single-request batches. It can answer the request with
// replies that are designed to test edge cases in clients. The sum of
// probabilities of all generators passed to |AddBrokenReplyGenerator| must
// be ≤ 1024.
bool AddBrokenReplyGenerator(std::unique_ptr<BrokenReplyGenerator> generator);
// ProcessBatch reads zero or more requests from |fd|, has |server| process
// them and sends out the replies. It returns false if there was an
// unexpected error during processing and true otherwise. (Reading zero
// packets, finding invalid requests etc are not counted as unexpected
// errors.)
virtual bool ProcessBatch(int fd, Server* server, Stats* out_stats);
// MakeSocket sets |*out_sock| to a UDP socket bound to the given port and
// sets |*out_port| to the bound port number. If |port| is zero then a free
// port number is used. It returns true on success or false on error.
static bool MakeSocket(int port, int* out_sock, uint16_t* out_port);
// See recvmmsg(2) for help understanding these. Note that indices in the
// sending arrays don't correspond 1:1 with indices in the receiving arrays,
// due to the possibility of invalid requests.
mmsghdr recv_mmsghdrs_[kBatchSize];
iovec recv_iov_[kBatchSize];
uint8_t recv_buf_[kBatchSize][kMaxRecvPacketSize];
mmsghdr send_mmsghdrs_[kBatchSize];
iovec send_iov_[kBatchSize];
uint8_t send_buf_[kBatchSize][kMaxResponseSize];
// PrepareResponse sets up |send_mmsghdrs[index]|.
virtual void PrepareResponse(struct msghdr* out_send_header,
const struct msghdr& recv_header);
// Reset clears state in order to prepare for recvmmsg(2).
virtual void Reset();
// MaybeBreakResponse takes a valid request in |request| and the standard
// response in |normal_response|. If any element of
// |broken_reply_generators_| should be applied then it does so. It returns
// true if the response in |out| should be sent and false if not.
bool MaybeBreakResponse(uint8_t* out, size_t* out_len, size_t max_out_len,
const uint8_t* normal_response,
size_t normal_response_len, const uint8_t* request,
size_t request_len);
sockaddr_storage sockaddrs_[kBatchSize];
// requests_processed_ is the total number of valid requests that have been
// processed.
uint64_t requests_processed_ = 0;
std::vector<std::unique_ptr<BrokenReplyGenerator>> broken_reply_generators_;
// broken_reply_generator_sum_ is the sum of the probabilities of
// |broken_reply_generators_|.
uint16_t broken_reply_generator_sum_ = 0;
} // namespace roughtime