wip on proxy

This commit is contained in:
Claudio Maggioni 2020-04-02 08:19:25 +02:00
commit 2f61f2f63f
1 changed files with 668 additions and 0 deletions

668
server.cc Normal file
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// vim: set ts=2 sw=2 et tw=80:
#include <cctype>
#include <arpa/inet.h>
#include <Magick++.h>
#include <sys/types.h>
#include <cstdint>
#include <sys/socket.h>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <unistd.h>
#include <pthread.h>
#include <iostream>
#include <map>
#include <vector>
#include <curl/curl.h>
#include <netdb.h>
using namespace std;
#define MAX_CLIENTS 128
#define BUFFER 8192
void* request_thread(void*);
// Do not kill process when socket connection is broken. Error is already
// handled
static void broken_pipe(int signo) {}
int sock_conn_d;
// Close socket when shutting down
static void sigint(int signo) {
close(sock_conn_d);
exit(0);
}
int main(int argc, char** argv) {
signal(SIGPIPE, broken_pipe);
Magick::InitializeMagick(*argv);
if(argc < 3) {
fprintf(stderr, "Give port and image_rotation\n");
exit(255);
}
int sock_data_d;
struct sockaddr_in server;
if((sock_conn_d = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("server socket not created");
exit(1);
}
memset(&server, 0, sizeof(server)); // zero the memory
server.sin_family = AF_INET;
server.sin_addr.s_addr = inet_addr("0.0.0.0");
server.sin_port = htons(atoi(argv[1]));
int reusePort = 1;
setsockopt(sock_conn_d, SOL_SOCKET, SO_REUSEPORT, &reusePort,
sizeof(reusePort));
if(::bind(sock_conn_d, (struct sockaddr*)&server, sizeof(server)) == -1) {
perror("server socket not bound");
exit(2);
}
while(true) {
if(listen(sock_conn_d, MAX_CLIENTS) != 0) {
perror("cannot listen on socket");
close(sock_conn_d);
exit(3);
}
printf("listening...\n");
struct sockaddr_in client;
socklen_t client_len = sizeof(client);
sock_data_d = accept(sock_conn_d, (struct sockaddr*)&client, &client_len);
if(sock_data_d == -1) {
perror("cannot accept client");
close(sock_conn_d);
exit(4);
}
int* fd = (int*) malloc(sizeof(int));
if (!fd) {
perror("thread creation failed");
exit(1);
}
*fd = sock_data_d;
pthread_t req;
pthread_create(&req, NULL, request_thread, (void*) fd);
}
}
bool empty_line(FILE* in) {
char a = fgetc(in), b = fgetc(in);
if (a == '\r' && b == '\n') {
return true;
} else {
ungetc(b, in);
ungetc(a, in);
return false;
}
}
bool parse_headers(FILE* in, map<string, string>& headers) {
while(true) {
// probe first two chars to see if body will start
if (empty_line(in)) {
break;
}
string header_name;
char c;
while((c = fgetc(in)) != ':') {
if (c == EOF || c == '\r' || c == '\n' || !isascii(c)) {
return false;
} else {
header_name += c;
}
}
do {
c = fgetc(in);
} while(isspace(c) && c != '\n' && c != '\r');
ungetc(c, in);
string value = "";
do {
c = fgetc(in);
value += c;
} while(c != '\r');
value.pop_back();
fgetc(in); // \n
headers[header_name] = value;
cout << header_name << ": " << value << endl;
}
return true;
}
bool has_body(char* method) {
return !strcmp(method, "POST") || !strcmp(method, "PUT");
}
bool is_chunk_start(char* buf) {
char* i;
for (i = buf; isdigit(*i); i++);
if (*i != '\r') return false;
i++;
if (*i != '\n') return false;
i++;
return *i == '\0';
}
bool fetch_body(FILE* in, vector<uint8_t>& body,
const map<string, string> headers) {
bool chunked;
size_t length, r = 0;
auto p = headers.find("Content-Length");
chunked = p == headers.end();
if (!chunked) {
length = atol(p->second.c_str());
} else {
auto q = headers.find("Transfer-Encoding");
if (q == headers.end() || q->second != "chunked") {
return false;
}
}
if (!chunked) {
// read Content-Length bytes
uint8_t buf[8192];
const size_t n = atol(p->second.c_str());
for(size_t w = 0; w < n;) {
ssize_t r = fread(buf, 1, (n - w) > 8192 ? 8192 : (n - w), in);
if (r == -1) return false;
body.insert(end(body), begin(buf), end(buf));
w += r;
}
} else {
// This was implemented before Prof. Carzaniga said chunked encoding is not
// required. I am leaving this just because it is already done.
// Read chunks and search for final chunk 0\r\n\r\n
char buf[8193];
bool chunk_start = true;
while (true) {
fgets(buf, 8193, in);
if (!strcmp(buf, "0\r\n") && chunk_start) {
break;
}
if (chunk_start && is_chunk_start(buf)) {
continue;
}
body.insert(end(body), begin(buf), end(buf));
body.pop_back();
char b = body.back();
body.pop_back();
char a = body.back();
body.pop_back();
if (a != '\r' || b != '\n') {
body.push_back(a);
body.push_back(b);
}
size_t len = strlen(buf);
chunk_start = len > 2 && buf[len-2] == '\r' && buf[len-1] == '\n';
}
body.insert(end(body), begin(buf), end(buf));
body.push_back(fgetc(in)); // \r
body.push_back(fgetc(in)); // \n
}
return true;
}
void send_error(FILE* in, FILE* out, const char* protocol, const int status,
const string message) {
const char* msg = message.c_str();
fprintf(out, "%s %d %s\r\n", protocol, status, msg);
fprintf(out, "Content-Type: text/html; charset=utf-8\r\n");
fprintf(out, "Connection: close\r\n");
cerr << status << ' ' << msg << endl;
char message_buf[4096];
message_buf[4095] = '\0';
snprintf(message_buf, 4095, "<!DOCTYPE html>\n"
"<html>\n"
" <head>\n"
" <meta charset=\"utf-8\"/>\n"
" <title>%s</title>\n"
" </head>\n"
" <body>\n"
" <h1>%s</h1>\n"
" </body>\n"
"</html>\n", msg, msg);
fprintf(out, "Content-Length: %lu\r\n\r\n", strlen(message_buf));
fprintf(out, "%s", message_buf);
fclose(in);
fflush(out);
fclose(out);
pthread_exit(NULL);
}
bool set_curl_method(CURL* c, const char* method) {
if (!strcmp(method, "GET")) {
curl_easy_setopt(c, CURLOPT_HTTPGET, 1);
} else if (!strcmp(method, "HEAD")) {
curl_easy_setopt(c, CURLOPT_HTTPGET, 1);
curl_easy_setopt(c, CURLOPT_NOBODY, 1);
} else if (!strcmp(method, "POST")) {
curl_easy_setopt(c, CURLOPT_POST, 1);
} else if (!strcmp(method, "PUT")) {
curl_easy_setopt(c, CURLOPT_PUT, 1);
} else if (!strcmp(method, "DELETE")) {
curl_easy_setopt(c, CURLOPT_CUSTOMREQUEST, "DELETE");
} else {
//TODO: implement CONNECT method
return false;
}
return true;
}
struct buffer {
size_t size;
uint8_t* data;
};
void buffer_init(struct buffer* self) {
self->size = 0;
self->data = (uint8_t*) malloc(8192);
if (self->data) {
self->data[0] = 0;
}
}
size_t write_buffer(void *ptr, size_t size, size_t nmemb,
struct buffer* rbody) {
size_t index = rbody->size;
size_t n = size * nmemb;
rbody->size += n;
uint8_t* newdata = (uint8_t*) realloc(rbody->data, rbody->size + 1);
if (!newdata) {
perror("reallocation of body buffer failed");
if (rbody->data) free(rbody->data);
rbody->data = NULL;
return 0;
} else {
rbody->data = newdata;
}
memcpy((rbody->data + index), ptr, n);
rbody->data[rbody->size] = '\0';
cout << "copy " << n << " size " << rbody->size << endl;
return size * nmemb;
}
// Converts url in a zero-terminated string for the host name. Port is retured
// as integer, -1 on error
int find_host_port(char* url) {
char* i = url;
size_t c = 0;
while (*i != ':' && *i != '\0') {
if (c >= 256 || (!isalnum(*i) && *i != '-' && *i != '.')) return -1;
i++;
c++;
}
if (c == 0) return -1;
*i = '\0';
i++;
if (*i == '\0') return 80;
unsigned p;
if (sscanf(i, "%5u", &p) == 1) {
return p < 65536 ? p : 80;
} else {
return 80;
}
}
struct forward {
int in;
int out;
};
bool total_write(uint8_t* data, size_t n, int out) {
for(size_t w = 0; w < n;) {
ssize_t written = write(out, data + w, n - w);
if (written == -1) {
return false;
}
w += written;
}
return true;
}
void* forwarder_thread(void* data) {
struct forward* f = (struct forward*) data;
const size_t BUF_SIZE = 65536;
uint8_t buffer[BUF_SIZE];
while (true) {
size_t r = read(f->in, buffer, BUF_SIZE);
if (r == 0) {
break;
}
if (!total_write(buffer, r, f->out)) {
cout << "Closing CONNECT forwaredr" << endl;
return NULL;
}
}
return NULL;
}
void handle_connect(FILE* in, FILE* out, const char* protocol, char* url,
const int fd) {
int port;
if ((port = find_host_port(url)) == -1) {
send_error(in, out, protocol, 500, "Hostname parse error");
}
int socketfd = socket(AF_INET, SOCK_STREAM, 0);
if (socketfd == -1) {
send_error(in, out, protocol, 500, "TCP socket connection error");
}
struct hostent *he = gethostbyname(url);
if (!he) {
send_error(in, out, protocol, 404, "Unknown host");
}
struct sockaddr_in locale;
memset (&locale, 0, sizeof(struct sockaddr_in));
locale.sin_family = AF_INET;
locale.sin_addr.s_addr = htonl(INADDR_ANY);
locale.sin_port = htons(0);
if (::bind(socketfd, (struct sockaddr*) &locale, sizeof(locale)) == -1) {
send_error(in, out, protocol, 500, "TCP socket connection error");
}
struct sockaddr_in remote;
memset (&remote, 0, sizeof(struct sockaddr_in));
remote.sin_family = he->h_addrtype;
memmove(&remote.sin_addr, he->h_addr, he->h_length);
remote.sin_port = htons((uint16_t) port);
if (connect(socketfd, (struct sockaddr*) &remote, sizeof(remote)) == -1) {
send_error(in, out, protocol, 500, "TCP socket connection error");
}
struct forward from = { .in = fd, .out = socketfd },
to = { .in = socketfd, .out = fd };
fprintf(out, "%s %d %s\r\n\r\n", protocol, 200, "Connection established");
fflush(out);
cout << "Connection established" << endl;
pthread_t ffrom;
pthread_create(&ffrom, NULL, forwarder_thread, &from);
forwarder_thread(&to);
pthread_join(ffrom, NULL);
}
struct read_buffer {
const vector<uint8_t>& body;
size_t index;
};
static size_t read_buffer(void *dest, size_t size, size_t nmemb, void *userp)
{
struct read_buffer *wt = (struct read_buffer*) userp;
size_t buffer_size = size * nmemb;
size_t remaining = wt->body.size() - wt->index;
if (buffer_size == wt->body.size()) {
return 0;
}
size_t chunk_len = remaining > buffer_size ? buffer_size : remaining;
auto start = wt->body.begin() + wt->index;
copy(start, start + chunk_len, (uint8_t*) dest);
wt->index += chunk_len;
return chunk_len;
}
void* request_thread(void* data) {
int fd = *((int*) data);
FILE* in = fdopen(dup(*((int*) data)), "r");
FILE* out = fdopen(dup(*((int*) data)), "w");
free(data);
while (true) {
char method[10];
char url[8000];
char protocol[10];
map<string, string> headers;
vector<uint8_t> body;
if (fscanf(in, "%10s %8000s %10s\r\n", method, url, protocol) < 3) {
send_error(in, out, protocol, 400, "Bad request line");
}
cout << "METHOD: " << method << " URL: " << url << " PROTOCOL: " << protocol
<< endl;
if (!parse_headers(in, headers)) {
send_error(in, out, protocol, 400, "Malformed header");
}
if (strncmp(url, "http", 4) && strcmp(method, "CONNECT")) {
send_error(in, out, protocol, 400, "Request line must contain absolute"
" URL (this is a proxy)");
}
cout << "BODY: " << endl;
// check if Content-Length is present and read Content-Length bytes
// check if Transfer-Encoding: chunked is present and wait for \r\n on a
// line
if (has_body(method)) {
if (!fetch_body(in, body, headers)) {
send_error(in, out, protocol, 411,
"No Content-Length or Transfer-Encoding");
}
}
cout << "PARSED" << endl;
if (!strcmp(method, "CONNECT")) {
handle_connect(in, out, protocol, url, fd);
break;
} else {
struct buffer rhead;
struct buffer rbody;
buffer_init(&rhead);
buffer_init(&rbody);
if(!rhead.data || !rbody.data) {
send_error(in, out, protocol, 500, "Failed to allocate response buffer");
}
CURL *curl;
curl = curl_easy_init();
if (!curl) {
send_error(in, out, protocol, 500, "Cannot init CURL");
}
if (!set_curl_method(curl, method)) {
send_error(in, out, protocol, 405, "Method not implemented");
}
curl_easy_setopt(curl, CURLOPT_URL, url);
// Delete Proxy-Connection header
{
auto i = headers.find("Proxy-Connection");
if (i != headers.end()) {
headers.erase(i);
}
}
struct curl_slist *chunk = NULL;
for (auto i = headers.begin(); i != headers.end(); i++) {
string header = i->first + ": " + i->second;
chunk = curl_slist_append(chunk, header.c_str());
}
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
if (has_body(method)) {
struct read_buffer r = { .body = body, .index = 0 };
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_buffer);
curl_easy_setopt(curl, CURLOPT_READDATA, &r);
chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
chunk = curl_slist_append(chunk, "Expect:");
}
curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, write_buffer);
curl_easy_setopt(curl, CURLOPT_HEADERDATA, &rhead);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_buffer);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &rbody);
CURLcode res = curl_easy_perform(curl);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
send_error(in, out, protocol, 502, "Request to server failed");
} else {
char protocol_r[10];
char message[8000];
unsigned code;
const char* image = NULL;
const char* const PNG = "PNG";
const char* const JPEG = "JPEG";
{
cout << "RESPONSE: " << endl;
FILE* res_head = fmemopen(rhead.data, rhead.size, "r");
fscanf(res_head, "%10s %3u %8000s\r\n", protocol_r, &code, message);
cout << "STATUS: " << code << " PROTOCOL: " << protocol_r << endl;
headers.empty();
parse_headers(res_head, headers);
auto a = headers.find("Content-Type");
if (a != headers.end()) {
if (a->second == "image/jpeg") image = JPEG;
else if (a->second == "image/png") image = PNG;
}
}
cout << "image: " << (image ? image : "NULL") << endl;
if (image) {
try {
Magick::Blob my_blob(rbody.data, rbody.size);
Magick::Blob output;
Magick::Image to_rotate(my_blob);
to_rotate.magick(image);
to_rotate.flip();
to_rotate.write(&output);
cout << "IN" << endl << my_blob.length() << endl;
cout << "OUT" << endl << output.length() << endl;
fprintf(out, "%s %u %s\n", protocol_r, code, message);
cout << protocol_r << ' ' << code << ' ' << message << endl;
headers["Content-Length"] = to_string(output.length());
for (auto i = headers.begin(); i != headers.end(); i++) {
string header = i->first + ": " + i->second + "\r\n";
fprintf(out, "%s\n", header.c_str());
cout << header << endl;
}
fprintf(out, "\r\n");
fflush(out);
total_write((uint8_t*) output.data(), output.length(), fd);
} catch (Magick::Exception &error) {
send_error(in, out, protocol, 500, "Image conversion failed");
fprintf(stderr, "I exit %s\n", error.what());
break;
} catch (std::exception &error) {
send_error(in, out, protocol, 500, "Image conversion failed");
fprintf(stderr, "I exit %s\n", error.what());
break;
}
} else {
total_write(rhead.data, rhead.size, fd);
total_write(rbody.data, rbody.size, fd);
fflush(out);
}
}
curl_easy_cleanup(curl);
curl_slist_free_all(chunk);
free(rhead.data);
free(rbody.data);
}
{
auto i = headers.find("Connection");
if (i != headers.end() && i->second == "close") {
break;
}
}
}
cout << "closing data socket...\n";
fclose(in);
fflush(out);
fclose(out);
pthread_exit(NULL);
}