From 424bcc25db6c3de73678fe43d44e4b408cd0434d
From: Peter Mikkelsen <petermikkelsen10@gmail.com>
Date: Wed, 23 Jun 2021 15:44:24 +0000
Subject: [PATCH] Initial buggy version of adding websocket support to webfs


It can create connections but doesn't handle errors very well yet.
---
diff ce73821f3575921e24f839b21c7be60520a9dc42 424bcc25db6c3de73678fe43d44e4b408cd0434d
--- a/sys/src/cmd/webfs/fns.h	Mon Jun 21 17:38:11 2021
+++ b/sys/src/cmd/webfs/fns.h	Wed Jun 23 17:44:24 2021
@@ -41,3 +41,6 @@
 int authenticate(Url *u, Url *ru, char *method, char *s);
 void flushauth(Url *u, char *t);
 void http(char *m, Url *u, Key *shdr, Buq *qbody, Buq *qpost);
+
+/* websocket */
+void websocket(int fd, Buq *qbody, Buq *qpost);
--- a/sys/src/cmd/webfs/fs.c	Mon Jun 21 17:38:11 2021
+++ b/sys/src/cmd/webfs/fs.c	Wed Jun 23 17:44:24 2021
@@ -4,6 +4,7 @@
 #include <fcall.h>
 #include <thread.h>
 #include <9p.h>
+#include <libsec.h>
 
 #include "dat.h"
 #include "fns.h"
@@ -19,10 +20,12 @@
 	Url	*baseurl;
 	Url	*url;
 	Key	*hdr;
+	int	wantwebsocket;
 
 	int	obody;	/* body opend */
 	int	cbody;	/* body closed */
 	Buq	*qbody;
+	Buq	*websocketin;	/* websocket input */
 };
 
 struct Webfid
@@ -121,6 +124,8 @@
 
 	buclose(cl->qbody, 0);
 	bufree(cl->qbody);
+	buclose(cl->websocketin, 0);
+	bufree(cl->websocketin);
 
 	while(k = cl->hdr){
 		cl->hdr = k->next;
@@ -384,6 +389,25 @@
 		if(cl->qbody == nil){
 			char *m;
 
+			if(f->level == Qbody && (!strcmp(cl->url->scheme, "ws") || !strcmp(cl->url->scheme, "wss"))){
+				cl->wantwebsocket = 1;
+				cl->websocketin = bualloc(64*1024);
+				if(!lookkey(cl->hdr, "Upgrade"))
+					cl->hdr = addkey(cl->hdr, "Upgrade", "websocket");
+				if(!lookkey(cl->hdr, "Connection"))
+					cl->hdr = addkey(cl->hdr, "Connection", "upgrade");
+				if(!lookkey(cl->hdr, "Sec-WebSocket-Version"))
+					cl->hdr = addkey(cl->hdr, "Sec-WebSocket-Version", "13");
+				if(!lookkey(cl->hdr, "Sec-WebSocket-Key")){
+					uchar nonce[16];
+					char *b64nonce;
+					genrandom(nonce, 16);
+					b64nonce = smprint("%.*[", 16, nonce);
+					cl->hdr = addkey(cl->hdr, "Sec-WebSocket-Key", b64nonce);
+					free(b64nonce);
+				}
+			}
+
 			if(cl->url == nil){
 				respond(r, "no url set");
 				return;
@@ -413,7 +437,7 @@
 			if(agent && !lookkey(cl->hdr, "User-Agent"))
 				cl->hdr = addkey(cl->hdr, "User-Agent", agent);
 
-			http(m, cl->url, cl->hdr, cl->qbody, f->buq);
+			http(m, cl->url, cl->hdr, cl->qbody, cl->wantwebsocket ? cl->websocketin : f->buq);
 			cl->request[0] = 0;
 			cl->url = nil;
 			cl->hdr = nil;
@@ -683,6 +707,11 @@
 	case Qpost:
 		bureq(f->buq, r);
 		return;
+	case Qbody:
+		if(f->client->wantwebsocket){
+			bureq(f->client->websocketin, r);
+			return;
+		}
 	}
 	respond(r, "not implemented");
 }
--- a/sys/src/cmd/webfs/http.c	Mon Jun 21 17:38:11 2021
+++ b/sys/src/cmd/webfs/http.c	Wed Jun 23 17:44:24 2021
@@ -131,7 +131,7 @@
 		if(strcmp(proxy->scheme, "https") == 0)
 			fd = tlswrap(fd, proxy->host);
 	} else {
-		if(strcmp(u->scheme, "https") == 0)
+		if(strcmp(u->scheme, "https") == 0 || strcmp(u->scheme, "wss") == 0)
 			fd = tlswrap(fd, u->host);
 	}
 	if(fd < 0){
@@ -520,7 +520,7 @@
 void
 http(char *m, Url *u, Key *shdr, Buq *qbody, Buq *qpost)
 {
-	int i, l, n, try, pid, fd, cfd, needlength, chunked, retry, nobody, badauth;
+	int i, l, n, try, pid, fd, cfd, needlength, chunked, retry, nobody, badauth, wantwebsocket;
 	char *s, *x, buf[8192+2], status[256], method[16], *host;
 	vlong length, offset;
 	Url ru, tu, *nu;
@@ -549,8 +549,13 @@
 		break;
 	}
 
+	if(!strcmp(u->scheme, "ws") || !strcmp(u->scheme, "wss"))
+		wantwebsocket = 1;
+	else
+		wantwebsocket = 0;
+
 	notify(catch);
-	if(qpost){
+	if(qpost && !wantwebsocket){
 		/* file for spooling the postbody if we need to restart the request */
 		snprint(buf, sizeof(buf), "/tmp/http.%d.%d.post", getppid(), getpid());
 		fd = create(buf, OEXCL|ORDWR|ORCLOSE, 0600);
@@ -565,7 +570,7 @@
 	badauth = 0;
 	for(try = 0; try < 12; try++){
 		strcpy(status, "0 No status");
-		if(u == nil || (strcmp(u->scheme, "http") && strcmp(u->scheme, "https"))){
+		if(u == nil || (strcmp(u->scheme, "http") && strcmp(u->scheme, "https") && strcmp(u->scheme, "ws") && strcmp(u->scheme, "wss"))){
 			werrstr("bad url scheme");
 			break;
 		}
@@ -591,7 +596,7 @@
 
 		length = 0;
 		chunked = 0;
-		if(qpost){
+		if(qpost && !wantwebsocket){
 			/* have to read it to temp file to figure out the length */
 			if(fd >= 0 && needlength && lookkey(shdr, "Content-Length") == nil){
 				seek(fd, 0, 2);
@@ -700,7 +705,7 @@
 			goto Retry;
 		}
 
-		if(qpost && !h->tunnel){
+		if(qpost && !h->tunnel && !wantwebsocket){
 			h->cancel = 0;
 			if((pid = rfork(RFMEM|RFPROC)) <= 0){
 				int ifd;
@@ -802,8 +807,42 @@
 				goto Status;
 			}
 			goto Error;
-		case 100:	/* Continue */
 		case 101:	/* Switching Protocols */
+			if(wantwebsocket){
+				int ok = 1;
+				char *wskey = lookkey(shdr, "Sec-WebSocket-Key");
+
+				k = getkey(rhdr, "Upgrade");
+				if(k == nil || cistrcmp(k->val, "websocket") != 0)
+					ok = 0;
+
+				k = getkey(rhdr, "Connection");
+				if(k == nil && cistrcmp(k->val, "upgrade") != 0)
+					ok = 0;
+
+				k = getkey(rhdr, "Sec-WebSocket-Accept");
+				if(k == nil || wskey == nil)
+					ok = 0;
+				else{
+					uchar digest[SHA1dlen];
+					char *str = smprint("%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", wskey);
+					
+					sha1((uchar*)str, strlen(str), digest, nil);
+					char *val = smprint("%.*[", SHA1dlen, digest);
+					if(strcmp(val, k->val) != 0)
+						ok = 0;
+					free(str);
+					free(val);
+				}
+		
+				if(ok){
+					qbody->url = u; u = nil;
+					qbody->hdr = rhdr; rhdr = nil;
+					websocket(h->fd, qbody, qpost);
+				}
+				goto Error;
+			}
+		case 100:	/* Continue */
 		case 102:	/* Processing */
 		case 103:	/* Early Hints */
 			while(k = rhdr){
--- a/sys/src/cmd/webfs/mkfile	Mon Jun 21 17:38:11 2021
+++ b/sys/src/cmd/webfs/mkfile	Wed Jun 23 17:44:24 2021
@@ -3,6 +3,6 @@
 TARG=webfs
 
 HFILES=fns.h dat.h
-OFILES=sub.$O url.$O buq.$O http.$O fs.$O
+OFILES=sub.$O url.$O buq.$O http.$O websocket.$O fs.$O
 
 </sys/src/cmd/mkone
--- /dev/null	Mon Jun 21 23:24:08 2021
+++ b/sys/src/cmd/webfs/websocket.c	Wed Jun 23 17:44:24 2021
@@ -0,0 +1,349 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include <libsec.h>
+
+#include "dat.h"
+#include "fns.h"
+
+typedef struct Frame Frame;
+typedef struct Message Message;
+
+struct Frame
+{
+	int	final;
+	int	opcode;
+	int	masked;
+	uchar	maskkey[4];
+	uvlong	length;
+	uchar	*data;
+
+	Frame	*next; /* Chain frames in a message together */
+};
+
+struct Message
+{
+	int	type;
+	uvlong	length;
+	uchar	*data;
+};
+
+enum {
+	ContinueFrame	= 0x0,
+	TextFrame	= 0x1,
+	BinaryFrame	= 0x2,
+	CloseFrame	= 0x8,
+	PingFrame	= 0x9,
+	PongFrame	= 0xA,
+};
+
+void writemessage(int, Message *);
+
+void
+maskframe(Frame *f)
+{
+	uvlong i;
+	for(i = 0; i < f->length; i++)
+		f->data[i] = f->data[i] ^ f->maskkey[i%4];
+}
+
+Frame *
+readframe(int fd)
+{
+	Frame *f = malloc(sizeof(Frame));
+	long n;
+	int offset;
+	uchar len;
+
+	uchar buf[4096];
+
+Again:
+	offset = 0;
+	n = read(fd, buf, 2);
+	if(n != 2)
+		goto Error;
+
+	f->final = (buf[offset] >> 7) & 0x1;
+	/* ignore rsv1, rsv2, rsv3 */
+	f->opcode = buf[offset] & 0x0F;
+	offset++;
+
+	f->masked = (buf[offset] >> 7) & 0x1;
+	len = buf[offset] & 0x7F;
+	offset++;
+
+	if(len <= 125)
+		f->length = len;
+	else if(len == 126){
+		n = read(fd, buf+offset, 2);
+		if(n != 2)
+			goto Error;
+		
+		f->length = buf[offset++] << 8;
+		f->length |= buf[offset++];
+	}else if(len == 127){
+		n = read(fd, buf+offset, 8);
+		if(n != 8)
+			goto Error;
+		f->length = (uvlong)buf[offset++] << 56;
+		f->length |= (uvlong)buf[offset++] << 48;
+		f->length |= (uvlong)buf[offset++] << 40;
+		f->length |= (uvlong)buf[offset++] << 32;
+		f->length |= buf[offset++] << 24;
+		f->length |= buf[offset++] << 16;
+		f->length |= buf[offset++] << 8;
+		f->length |= buf[offset++];
+	}
+
+	if(f->masked){
+		n = read(fd, buf+offset, 4);
+		if(n != 4)
+			goto Error;
+
+		f->maskkey[0] = buf[offset++];
+		f->maskkey[1] = buf[offset++];
+		f->maskkey[2] = buf[offset++];
+		f->maskkey[3] = buf[offset];
+	}
+
+	f->data = malloc(f->length);
+	readn(fd, f->data, f->length);
+	if(f->masked)
+		maskframe(f);
+
+	if(f->opcode == PingFrame){
+		Message *m = malloc(sizeof(Message));
+		m->type = PongFrame;
+		m->length = f->length;
+		m->data = f->data;
+		writemessage(fd, m); /* SHOULD LOCK */
+		free(m);
+		free(f->data);
+		goto Again;
+	}
+
+	return f;
+Error:
+	exits("Readframe failed");
+	return nil;
+}
+
+Message *
+framestomessage(Frame *frames)
+{
+	Message *m = malloc(sizeof(Message));
+	uvlong length = 0;
+	uvlong offset = 0;
+
+	Frame *f;
+	for(f = frames; f != nil; f = f->next)
+		length += f->length;
+
+	m->type = frames->opcode;
+	m->length = length;
+	m->data = malloc(length);
+	for(f = frames; f != nil; f = f->next){
+		memcpy(m->data + offset, f->data, f->length);
+		offset += f->length;
+	}
+
+	return m;
+}
+
+Message *
+readmsg(int fd)
+{
+	Frame *frames = readframe(fd);
+	Frame *last = frames;
+	Message *m;
+
+	while(!last->final){
+		last->next = readframe(fd);
+		last = last->next;
+	}
+	last->next = nil;
+
+	m = framestomessage(frames);
+	while(frames){
+		Frame *f = frames->next;
+		free(frames->data);
+		free(frames);
+		frames = f;
+	}
+	return m;
+}
+
+void
+writeframe(int fd, Frame *f)
+{
+	uchar *buf;
+	uvlong totsize = 0;
+	uvlong offset = 0;
+	int lenbytes = 0;
+
+	totsize += 2; /* Always there */
+	if(f->length == 126)
+		lenbytes = 2;
+	else if(f->length == 127)
+		lenbytes = 8;
+	totsize += lenbytes;
+
+	if(f->masked)
+		totsize += 4;
+	
+	totsize += f->length;
+
+	buf = malloc(totsize);
+
+	buf[offset] = f->final << 7;
+	buf[offset++] |= f->opcode;
+	buf[offset] = f->masked << 7;
+
+	if(lenbytes == 0)
+		buf[offset++] |= f->length;
+	else if(lenbytes == 2)
+		buf[offset++] |= 126;
+	else if(lenbytes == 8)
+		buf[offset++] |= 127;
+
+	if(lenbytes == 2){
+		buf[offset++] = 0xFF & (f->length >> 8);
+		buf[offset++] = 0xFF & f->length;
+	}else if(lenbytes == 8){
+		buf[offset++] = 0xFF & (f->length >> 56);
+		buf[offset++] = 0xFF & (f->length >> 48);
+		buf[offset++] = 0xFF & (f->length >> 40);
+		buf[offset++] = 0xFF & (f->length >> 32);
+		buf[offset++] = 0xFF & (f->length >> 24);
+		buf[offset++] = 0xFF & (f->length >> 16);
+		buf[offset++] = 0xFF & (f->length >> 8);
+		buf[offset++] = 0xFF & f->length;
+	}
+
+	if(f->masked){
+		buf[offset++] = f->maskkey[0];
+		buf[offset++] = f->maskkey[1];
+		buf[offset++] = f->maskkey[2];
+		buf[offset++] = f->maskkey[3];
+	}
+
+	memcpy(buf + offset, f->data, f->length);
+	write(fd, buf, totsize);
+}
+
+void
+writemessage(int fd, Message *m)
+{
+	/* Could split up the message into frames but not right now. */
+
+	Frame *f = malloc(sizeof(Frame));
+	f->final = 1;
+	f->opcode = m->type;
+	f->masked = 1;
+	genrandom(f->maskkey, 4);
+	f->length = m->length;
+	f->data = malloc(f->length);
+	memcpy(f->data, m->data, f->length);
+	maskframe(f);
+	f->next = nil;
+	
+	writeframe(fd, f);
+	free(f->data);
+	free(f);
+}
+
+void
+websocketrecv(int fd, Buq *qbody)
+{
+	/*
+	 * Plan: Read frames and when we have a whole message do:
+	 * 1) If control, act on it
+	 * 2) If data, format as text and buwrite it
+	*/
+	while(1){
+		Message *m = readmsg(fd);
+		//print("Received message type=%d length=%ulld\n", m->type, m->length);
+
+		if(m->type == TextFrame || m->type == BinaryFrame){
+			char *header;
+			if(m->type == TextFrame)
+				header = smprint("t %0.20ulld", m->length);
+			else
+				header = smprint("b %0.20ulld", m->length);
+			buwrite(qbody, header, 22);
+			buwrite(qbody, m->data, m->length);
+		}
+		free(m->data);
+		free(m);
+	}
+}
+
+void
+websocketsend(int fd, Buq *qpost)
+{
+	/* buread messages and pack them up in frames and send them */
+	char buf[64];
+	long n;
+	Message *m;
+	while(1){
+		n = buread(qpost, buf, 22);
+		if(n != 22){
+			buclose(qpost, "Header short");
+			return;
+		}
+		buf[n] = 0;
+
+		m = malloc(sizeof(Message));
+		if(buf[0] == 't')
+			m->type = TextFrame;
+		else if(buf[0] == 'b')
+			m->type = BinaryFrame;
+
+		char *ret;
+		m->length = strtoull(buf+2, &ret, 10);
+		if(ret != buf+22){
+			buclose(qpost, "Header format wrong");
+			return;
+		}
+
+		m->data = malloc(m->length);
+		n = 0;
+		while(n < m->length){
+			uvlong missing = m->length - n;
+			n += buread(qpost, m->data + n, (missing < 8192) ? missing : 8192);
+		}
+
+		writemessage(fd, m);
+		free(m->data);
+		free(m);
+	}
+}
+
+void
+websocket(int fd, Buq *qbody, Buq *qpost)
+{
+	buwrite(qbody, "websocket ready\n", 16);
+	switch(rfork(RFPROC|RFMEM)){
+	default:
+		websocketrecv(fd, qbody);
+		break;
+	case 0:
+		websocketsend(fd, qpost);
+		goto End;
+	case -1:
+		buclose(qbody, "can't fork");
+		bufree(qbody);
+		buclose(qpost, "can't fork");
+		bufree(qpost);
+		break;
+	}
+End:
+	close(fd);
+	buclose(qbody, nil);
+	bufree(qbody);
+	buclose(qpost, nil);
+	bufree(qpost);
+	exits(nil);
+}