.gitignore

@@ -1,4 +1,3 @@
 *.o
 proxy
 compile_commands.json
-.cache

README

@@ -4,17 +4,12 @@
 
     Proxy C library for HTTP/s protocol 
 
-    NOTE: I have yet to turn this piece of clutter into a library. 
-
     RFC: datatracker.ietf.org/doc/html/rfc1945
     RES: cs.princeton.edu/courses/archive/spr13/cos461/assignments-proxy.html
     RES: Beej's Guide to Network Programming - Using Internet Sockets
     RES: en.wikipedia.org/wiki/Proxy_server
     RES: TCP/IP sockets in C - Practical guide for programmers 2nd edition
 
-    RES: tinyproxy.github.io/
-    RES: github.com/nginx/nginx
-
 TECHNICALS 
 
     * Parsing is carried by a dedicated sub-library which I wrote named parslib.
@@ -23,10 +18,6 @@ TECHNICALS
     no matter the amount of strings you want to compare it against (I am indeed 
     aware it is nonetheless worse than hashtables - maybe one day I will implement 
     those on my own as well).
-    * After the connection is established with the upstream server, a relay loop 
-    is started in which the client data is relayed to the server's socket and 
-    server data is relayed to client's socket. This is highly inspired from 
-    tinyproxy.
 
 TASKS
 
@@ -35,16 +26,15 @@ TASKS
         [DONE] Implement client message parsing
         [DONE] Implement server message parsing
     [DONE] Add loose string checking for headers
-    [DONE] Relaying mechanism
     [DOING] Cover all possible body segmentation standards
         [DONE] Cover Content-Length
-        [DONE] Cover "chunked transfer encoding"
-        [TODO] Cover "compress transfer encoding"
-        [TODO] Cover "deflate transfer encoding"
-        [TODO] Cover "gzip/x-gzip transfer encoding"
+        [DOING] Cover "chunked transfer encoding"
+        [DOING] Cover "compress transfer encoding"
+        [DOING] Cover "deflate transfer encoding"
+        [DOING] Cover "gzip/x-gzip transfer encoding"
     [ACTIVELY DOING] More testing, debugging, fixing
     [ACTIVELY DOING] Verify and search for memory leaks
-    [TODO] Implement HTTPS
+    [TODO] Implement HTTPS with OpenSSL, LibreSSL, or BearSSL
     [TODO] Caching?
 
 COMMITS

proxlib.c

@@ -7,14 +7,12 @@
 #include <arpa/inet.h>
 #include <netinet/in.h>
 #include <netdb.h>
-#include <poll.h>
 #include "proxlib.h"
 #include "parslib/parslib.h"
 
 int on = 1; 
-int debug = 1;
-int statem = 0; 
-int err = 0;
+int debug = 3;
+int statem; 
 
 #define SEGMENT_LEN 512
 #define MAX_BUFF_LEN 128 * 1024
@@ -94,107 +92,181 @@ int read_line(int fd,
     return 0;
 }
 
-int pull_content_length(int fd, int len, int *msgbuff_len, char **msgbuff) {
+int parse_line(char *line, int line_count) {
     int ret = 0; 
-    int line_len = len;
-    char *line = (char *) calloc(1, line_len);
+
+    return ret;
+}
+
+void do_err(void) {
+    int statem_code = statem & (~STATEM_ERR);
+    fprintf(stderr, "[%d,%d,%d] Errored out!\n", statem, statem_code,
+            STATEM_ERR);
+}
+
+int do_fwd_clt(struct conn *conn) {
+    int bytes = 0;
+    int ret = 0;
+    while (bytes < conn->srvbuff_len) {
+        ret = write(conn->cltfd, conn->srvbuff+bytes, conn->srvbuff_len-bytes);
+        if (ret < 0)
+            return -1;
+
+        bytes += ret;
+    }
+
+    return 0;
+}
+
+int do_rcv_srv(struct conn *conn) {
+    int ret = 0;
+    char *line = NULL; 
+    char *msgbuff = NULL;
+    int line_len = 0; 
+    int msgbuff_len = 0;
+
+    // response line 
+    ret = read_line(conn->srvfd, &line_len, &line, &msgbuff_len, &msgbuff);
+    if (ret < 0) {
+        fprintf(stderr, "Failed receiving response line from upstream\n");
+        return -1;
+    }
+
+    if (debug == 1) {
+        fprintf(stdout, "debug - [upstream] received line: %s\n", line);
+    }
+
+    ret = parestitl(line, line_len, &(conn->srvres.titl));    
+    if (ret < 0) {
+        fprintf(stderr, "Failed parsing response line\n");
+        return -1;
+    }
+
+    if (debug == 1) {
+        fprintf(stdout, "debug - [upstream] parsed response line\n");
+    }
+
+    free(line);
+
+    // headers
+    int next_header = 1; 
+    while (next_header) {
+        ret = read_line(conn->srvfd, &line_len, &line, &msgbuff_len, &msgbuff);
+        if (ret < 0) {
+            fprintf(stderr, "Failed receiving header line\n");
+            return -1;
+        }
+
+        if (line_len == 0) {
+            if (debug == 1) {
+                fprintf(stdout, "debug - [upstream] reached end of headers\n");
+            }
+            next_header = 0;
+            continue;
+        }
+
+        if (debug == 1) {
+            fprintf(stdout, "debug - [upstream] received line: %s\n", line);
+        }
+
+        ret = parshfield(line, line_len, conn->srvres.hentries);
+        if (ret < 0) {
+            fprintf(stderr, "Failed parsing header field\n");
+            return -1;
+        }
+
+        if (debug == 1) {
+            fprintf(stdout, "debug - parsed header field\n");
+        }
+
+        free(line);
+    }
+
+    // body
+body:
+    struct httpares *res = &conn->srvres;
+    struct point *content_length_entry = &res->hentries[header_content_length];
+    if (content_length_entry->er == NULL) {
+        fprintf(stderr, "[upstream] no content length header\n");
+        return -1;
+    }
+
+    int content_length = 0;
+    ret = stoin(content_length_entry->er, content_length_entry->len, &content_length);
+    if (ret < 0) {
+        fprintf(stderr, "[upstream] failed parsing content length header\n");
+        return -1;
+    }
+
+    line_len = content_length;
+    line = (char *) calloc(1, line_len);
     if (!line) {
-        return ERR_MEM;
+        fprintf(stderr, "[upstream] not enough dynamic memory\n");
+        return -1;
     }
 
     int bytes = 0;
     do {
-        ret = recv(fd, line+bytes, line_len-bytes, MSG_WAITALL);
+        ret = recv(conn->srvfd, line+bytes, line_len-bytes, MSG_WAITALL);
         if (ret < 0) {
-            return ERR_MEM;
+            fprintf(stderr, "[upstream] failed reading body from response\n");
+            return -1;
         }
         bytes += ret;
     } while (bytes < line_len);
 
-    *msgbuff = (char *) realloc(*msgbuff, *msgbuff_len+line_len);
-    if (!*msgbuff) {
-        return ERR_MEM;
+    msgbuff = (char *) realloc(msgbuff, msgbuff_len+line_len);
+    if (!msgbuff) {
+        fprintf(stderr, "[upstream] not enough dynamic memory\n");
+        return -1;
     }
 
-    memcpy(*msgbuff+*msgbuff_len, line, line_len);
-    *msgbuff_len += line_len;
+    memcpy(msgbuff+msgbuff_len, line, line_len);
+    msgbuff_len += line_len;
+
+    if (debug <= 2) {
+        fprintf(stdout, "------------------------------\n");
+        fprintf(stdout, "debug - [upstream] received body %d: %.*s\n", line_len, line_len, line);
+        fprintf(stdout, "------------------------------\n");
+    }
+
+    if (debug <= 2) {
+        fprintf(stdout, "printing parsed response\n");
+        printfpares(&conn->srvres);
+    }
+
+    conn->srvbuff = msgbuff;
+    conn->srvbuff_len = msgbuff_len;
 
     return 0; 
 }
 
-int pull_chunked_encoding(int fd, int *msgbuff_len, char **msgbuff) {
-	int ret = 0; 
-	char *line = NULL;
-	int line_len = 0; 
-
-	while (1) {
-		ret = read_line(fd, &line_len, &line, msgbuff_len, msgbuff);
-		if (ret < 0) {
-			fprintf(stderr, "Failed receiving chunked body from upstream\n");
-			return -1;
-		}
-
-		line_len = strtol(line, (char **) 0, 16); 
-		if (!line_len) {
-			break;
-		}
-
-		line_len += 2;
-
-		free(line);
-
-		line = (char *) calloc(1, line_len);
-		if (!line) {
-			fprintf(stderr, "Not enough dynamic memory\n");
-			return -1;
-		}
-
-		int bytes = 0; 
-		do {
-			ret = recv(fd, line+bytes, line_len-bytes, MSG_WAITALL); 
-			if (ret < 0) {
-				fprintf(stderr, "Failed reading respones body from server\n");
-				return -1;
-			}
-			bytes += ret;
-		} while (bytes < line_len); 
-
-		*msgbuff = (char *) realloc(*msgbuff, *msgbuff_len+line_len);
-		if (!msgbuff) {
-			fprintf(stderr, "Not enough dynamic memory\n");
-			return -1;
-		}
-
-		memcpy(*msgbuff+*msgbuff_len, line, line_len);
-		*msgbuff_len += line_len;
-		free(line);
-	}
-    return 0;
-
-}
-
-void do_err(void) {
-    fprintf(stderr, "failed with error code %d\n", err);
-}
-
 int do_con_srv(struct conn *conn) {
-    statem = state_con_srv;
-
     int ret = 0;
     struct httpareq *req = &conn->cltreq;
     struct point *host = &req->hentries[header_host];
     if (host->er == NULL) {
-        return ERR_PARS;
+        if (debug <= 2) {
+            fprintf(stderr, "debug - request does not have HOST header\n");
+        }
+        goto _exit;
     }
 
     struct hostinfo *info = (struct hostinfo *) calloc(1, sizeof(struct hostinfo));
     if (!info) {
-        return ERR_MEM;
+        goto _exit;
     }
 
     ret = pahostinfo(host->er, host->len, info);
     if (ret < 0) {
-        return ERR_PARS;
+        if (debug <= 2) {
+            fprintf(stderr, "Failed parsing upstream host header\n");
+        }
+        goto _exit_hostinfo;
+    }
+
+    if (debug <= 2) {
+        fprintf(stdout, "Establishing connection with upstream: %.*s : %.*s\n", info->hostname_len, info->hostname, info->service_len, info->service);
     }
 
     struct addrinfo hints; 
@@ -206,37 +278,45 @@ int do_con_srv(struct conn *conn) {
 
     ret = getaddrinfo(info->hostname, info->service, &hints, &res);
     if (ret < 0) {
-        free(info->hostname);
-        free(info->service);
-        free(info);
-        return ERR_PARS;
+        goto _exit_hostinfo;
     }
 
     ret = conn->srvfd = socket(res->ai_family, res->ai_socktype,
             res->ai_protocol);
     if (ret < 0) {
-        freeaddrinfo(res);
-        free(info->hostname);
-        free(info->service);
-        free(info);
-        return ERR_PARS;
+        goto _exit_getaddrinfo;
     }
 
     ret = connect(conn->srvfd, res->ai_addr, res->ai_addrlen);
     if (ret < 0) {
-        freeaddrinfo(res);
-        free(info->hostname);
-        free(info->service);
-        free(info);
-        return ERR_PARS;
+        goto _exit_getaddrinfo;
     }
 
+_exit_getaddrinfo:
+    freeaddrinfo(res);
+_exit_hostinfo:
+    free(info->hostname);
+    free(info->service);
+    free(info);
+_exit:
     return ret;
 }
 
-int do_rcv_clt(struct conn *conn) {
-    statem = state_rcv_clt;
+int do_fwd_srv(struct conn *conn) {
+    int bytes = 0;
+    int ret = 0;
+    while (bytes < conn->cltbuff_len) {
+        ret = write(conn->srvfd, conn->cltbuff+bytes, conn->cltbuff_len-bytes);
+        if (ret < 0)
+            return -1;
 
+        bytes += ret;
+    }
+
+    return 0;
+}
+
+int do_rcv_clt(struct conn *conn) {
     int ret = 0;
     char *line = NULL; 
     char *msgbuff = NULL;
@@ -246,12 +326,22 @@ int do_rcv_clt(struct conn *conn) {
     // request line 
     ret = read_line(conn->cltfd, &line_len, &line, &msgbuff_len, &msgbuff);
     if (ret < 0) {
-        return ERR_RECV;
+        fprintf(stderr, "Failed receiving request line\n");
+        return -1;
+    }
+
+    if (debug == 1) {
+        fprintf(stdout, "debug - received line: %s\n", line);
     }
 
     ret = pareqtitl(line, line_len, &(conn->cltreq.titl));    
     if (ret < 0) {
-        return ERR_PARSTITLE;
+        fprintf(stderr, "Failed parsing request line\n");
+        return -1;
+    }
+
+    if (debug == 1) {
+        fprintf(stdout, "debug - parsed request line\n");
     }
 
     free(line);
@@ -261,43 +351,41 @@ int do_rcv_clt(struct conn *conn) {
     while (next_header) {
         ret = read_line(conn->cltfd, &line_len, &line, &msgbuff_len, &msgbuff);
         if (ret < 0) {
-            return ERR_RECV;
+            fprintf(stderr, "Failed receiving header line\n");
+            return -1;
         }
 
         if (line_len == 0) {
+            if (debug == 1) {
+                fprintf(stdout, "debug - reached end of headers\n");
+            }
             next_header = 0;
             continue;
         }
 
+        if (debug == 1) {
+            fprintf(stdout, "debug - received line: %s\n", line);
+        }
+
         ret = parshfield(line, line_len, conn->cltreq.hentries);
         if (ret < 0) {
-            return ERR_PARSHEADER;
+            fprintf(stderr, "Failed parsing header field\n");
+            return -1;
+        }
+
+        if (debug == 1) {
+            fprintf(stdout, "debug - parsed header field\n");
         }
 
         free(line);
     }
 
     // body
-    struct httpareq *req = &conn->cltreq;
-    struct point *content_length_entry = &req->hentries[header_content_length];
-    struct point *transfer_encoding_entry = &req->hentries[header_transfer_encoding];
-    if (content_length_entry->er) {
-        int content_length = 0;
+    // TODO
 
-        ret = stoin(content_length_entry->er, content_length_entry->len, &content_length);
-        if (ret < 0) {
-            return ERR_PARS;
-        }
-
-        ret = pull_content_length(conn->srvfd, content_length, &msgbuff_len, &msgbuff);
-        if (ret < 0) {
-            return ERR_RECV;
-        }
-    } else if (transfer_encoding_entry->er && strcmp(transfer_encoding_entry->er, "chunked") == 0) {
-	    ret = pull_chunked_encoding(conn->srvfd, &msgbuff_len, &msgbuff);
-	    if (ret < 0) {
-            return ERR_RECV;
-	    }
+    if (debug <= 2) {
+        fprintf(stdout, "printing parsed request\n");
+        printfpareq(&conn->cltreq);
     }
 
     conn->cltbuff = msgbuff;
@@ -306,125 +394,51 @@ int do_rcv_clt(struct conn *conn) {
     return 0; 
 }
 
-int read_buffer(int fd, char **buff, int *len) {
-    char *tmp = (char *) malloc(RELAY_BUFFER_SIZE);
-    if (!tmp) {
-        return ERR_MEM;
-    }
-
-    memset(tmp, 0, RELAY_BUFFER_SIZE);
-    int bytes = recv(fd, tmp, RELAY_BUFFER_SIZE, 0);
-    if (bytes <= 0) {
-        free(tmp);
-        return ERR_RECV;
-    }
-
-    *buff = realloc(*buff, *len+bytes);
-    if (!*buff) {
-        free(tmp);
-        return ERR_MEM;
-    }
-
-    memcpy(*buff+*len, tmp, bytes);
-    *len += bytes;
-
-    return 0;
-}
-
-int write_buffer(int fd, char **buff, int *len) {
-    if (*len <= 0) {
-        *len = 0;
-        return 0;
-    }
-
-    int writen = send(fd, *buff, *len, 0); 
-    if (writen < 0) {
-        return ERR_SEND;
-    }
-
-    char *trunc = (char *) malloc(*len-writen);
-    if (!trunc) {
-        return ERR_MEM;
-    }
-
-    memcpy(trunc, *buff+writen, *len-writen);
-    
-    char *tofree = *buff; // FIXME: any better solution? 
-    *buff = trunc;
-    *len -= writen;
-    free(tofree);
-
-    return 0;
+void do_clear(struct conn *conn) {
+    statem = STATEM_RCV_CLT;
+    frepareq(&conn->cltreq);
+    frepares(&conn->srvres);
+    free(conn->cltbuff);
+    free(conn->srvbuff);
 } 
 
 void do_statem(struct conn *conn) {
     int ret = 0;
 
-    ret = do_rcv_clt(conn); 
-    if (ret < 0) {
-        err = ret;
-        do_err();
-    }
-
-    ret = do_con_srv(conn);
-    if (ret < 0) {
-        err = ret;
-        do_err();
-    }
-
-    // relay the data between the two sockets until the end of time
-    ssize_t bytes_received;
-	struct pollfd fds[2];
-    for (;;) {
-	    memset(fds, 0, 2*sizeof(struct pollfd));
-        fds[0].fd = conn->cltfd;
-        fds[1].fd = conn->srvfd;
-
-        if (conn->srvbuff_len > 0) {
-            fds[0].events |= POLLOUT;
-        }
-        if (conn->cltbuff_len > 0) {
-            fds[1].events |= POLLOUT;
-        }
-        if (!conn->srvbuff_len) {
-            fds[1].events |= POLLIN;
-        }
-        if (!conn->cltbuff_len) {
-            fds[0].events |= POLLIN;
-        }
-
-        ret = poll(fds, 2, 1000);
-
-        if (fds[1].revents & POLLOUT) {
-            ret = write_buffer(conn->srvfd, &conn->cltbuff, &conn->cltbuff_len);
-        }
-        if (fds[1].revents & POLLIN) {
-            ret = read_buffer(conn->srvfd, &conn->srvbuff, &conn->srvbuff_len);
-        }
-        if (fds[0].revents & POLLIN) {
-            ret = read_buffer(conn->cltfd, &conn->cltbuff, &conn->cltbuff_len);
-        }
-        if (fds[0].revents & POLLOUT) {
-            ret = write_buffer(conn->cltfd, &conn->srvbuff, &conn->srvbuff_len);
-        }
-        if (fds[0].revents & POLLHUP) {
+    for (int counter = 0; counter < MAX_BOUND; counter++) {
+        switch (statem & (~STATEM_ERR)) {
+        case STATEM_RCV_CLT:
+            ret = do_rcv_clt(conn);
+            break;
+        case STATEM_CON_SRV:
+            ret = do_con_srv(conn);
+            break;
+        case STATEM_FWD_SRV: 
+            ret = do_fwd_srv(conn);
+            break;
+        case STATEM_RCV_SRV: 
+            ret = do_rcv_srv(conn);
+            break;
+        case STATEM_FWD_CLT: 
+            ret = do_fwd_clt(conn);
             break;
         }
-        if (ret < 0) {
+
+        if (ret < 0) 
+            statem |= STATEM_ERR;
+
+        if (statem & STATEM_ERR) {
+            do_err();
             break;
         }
-    }
 
-    if (conn->cltbuff_len > 0) {
-        write_buffer(conn->srvfd, &conn->cltbuff, &conn->cltbuff_len);
-    }
-    if (conn->srvbuff_len > 0) {
-        write_buffer(conn->cltfd, &conn->srvbuff, &conn->srvbuff_len);
-    }
+        if (statem & STATEM_FWD_CLT) {
+            do_clear(conn);
+            continue;
+        }
 
-    close(conn->cltfd);
-    close(conn->srvfd);
-    exit(0); // child die
+        statem <<= 1;
+    }
 }
 
 int do_srv(void) {
@@ -462,8 +476,9 @@ int do_srv(void) {
 		return -1;
 	}
 
+	fprintf(stdout, "Listening on port %d\n", PROXY_PORT);
+
 	for (;;) {
-		fprintf(stdout, "listening for sockets\n");
 		struct sockaddr_in new_clt_addr; 
         socklen_t new_clt_addr_len= sizeof(new_clt_addr);
 		int new_clt_sock; 
@@ -475,7 +490,6 @@ int do_srv(void) {
                             "client\n");	
 			return -1;
 		}
-		fprintf(stdout, "accepted new client socket\n");
 
         ret = fork();
         if (ret < 0) {
@@ -485,11 +499,12 @@ int do_srv(void) {
         } 
 
         if (ret > 0) {
-            fprintf(stdout, "+new request process:%d(pid)\n", ret);
+            fprintf(stdout, "[PROGRAM] Successfully forked a new child process"
+                            " with PID %d\n", ret);
             continue;
         }
 
-        // request process
+        // child 
         struct conn *conn = (struct conn *) calloc(1, sizeof(struct conn));
         if (!conn) {
             fprintf(stderr, "Not enough dynamic memory to establish connection\n");
@@ -497,9 +512,14 @@ int do_srv(void) {
         }
 
         conn->cltfd = new_clt_sock;
-        statem = state_rcv_clt;
+        statem = STATEM_RCV_CLT;
         do_statem(conn);
         free(conn);
+
+        if (debug == 1) {
+            fprintf(stdout, "Finished proxying client\n");
+        }
+
         return 0;
 	}
 
@@ -513,10 +533,7 @@ int main(int argc, char *argv[]) {
         return -1;
     } 
 
-    ret = do_srv();
-    if (ret < 0) {
-        return -1;
-    }
+    return do_srv();
 
     fretres();
 }

proxlib.h

@@ -4,41 +4,18 @@
 #include "parslib/parslib.h"
 
 #ifndef MAX_BOUND
-#define MAX_BOUND 100000000000
+#define MAX_BOUND 10000
 #endif
 
 #define PROXY_PORT 2020
 #define PROXY_CONN 20
-#define RELAY_BUFFER_SIZE 1024*2
-#define RELAY_POLL_TIMEOUT 1000
 
-enum states {
-    state_rcv_clt = 0,
-    state_con_srv,
-    state_fwd_srv,
-    state_rcv_srv,
-    state_fwd_clt,
-    state_ok
-};
-
-#define ERR_GENERIC     -1 
-#define ERR_MEM         -2
-#define ERR_RECV        -3
-#define ERR_SEND        -4
-#define ERR_PARS        -5
-#define ERR_PARSTITLE   -6
-#define ERR_PARSHEADER  -7
-#define ERR_SUPPORT     -8
-#define ERR_TIMEOUT     -9
-
-char *states_str[] = {
-    "state_rcv_clt",
-    "state_con_srv",
-    "state_fwd_srv",
-    "state_rcv_srv",
-    "state_fwd_clt",
-    "state_ok"
-};
+#define STATEM_RCV_CLT 0b00000001
+#define STATEM_CON_SRV 0b00000010
+#define STATEM_FWD_SRV 0b00000100
+#define STATEM_RCV_SRV 0b00001000
+#define STATEM_FWD_CLT 0b00010000
+#define STATEM_ERR     0b00100000
 
 struct conn {
     int cltfd;