Clarified the dscp-tos documentation a bit.

[doldaconnect.git] / daemon / fnet-adc.c

/*
 *  Dolda Connect - Modular multiuser Direct Connect-style client
 *  Copyright (C) 2004 Fredrik Tolf <fredrik@dolda2000.com>
 *  
 *  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 2 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <wctype.h>
#include <iconv.h>
#include <errno.h>

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "filenet.h"
#include "log.h"
#include "module.h"
#include "utils.h"
#include "client.h"
#include "transfer.h"
#include "sysevents.h"
#include "net.h"
#include <tiger.h>

/* Protocol states */
#define ADC_PROTOCOL 0
#define ADC_IDENTIFY 1
#define ADC_VERIFY 2
#define ADC_NORMAL 3
#define ADC_DATA 4

struct command {
    wchar_t *name;
    int minargs, needsid, needsender;
    void (*func)(struct fnetnode *fn, wchar_t *command, wchar_t *sender, int argc, wchar_t **argv);
};

struct qcmd {
    struct qcmd *next;
    wchar_t **args;
};

struct qcmdqueue {
    struct qcmd *f, *l;
    int size;
};

struct adchub {
    struct socket *sk;
    char *inbuf;
    size_t inbufdata, inbufsize;
    wchar_t *sid;
    wchar_t *cb;
    size_t cbdata, cbsize;
    wchar_t **sup;
    iconv_t ich;
    int state;
    struct wcspair *hubinf;
    struct qcmdqueue queue;
};

static wchar_t *eoc, *ns, *fmt;
/* I've never understood why both of these are necessary, but... */
static wchar_t *privid, *cid;
struct socket *udpsock, *tcpsock;

static wchar_t **parseadc(wchar_t *cmdline)
{
    wchar_t **ret;
    size_t retsize, retdata;
    wchar_t *p, *p2, *ep;
    wchar_t r;
    ssize_t len;
    
    ret = NULL;
    retsize = retdata = 0;
    p = cmdline;
    do {
	if((p2 = wcschr(p, L' ')) != NULL)
	    *(p2++) = L'\0';
	len = wcslen(p);
	for(ep = p; len > 0; ep++, len--) {
	    if(*ep == L'\\') {
		if(ep[1] == L's') {
		    r = L' ';
		} else if(ep[1] == L'n') {
		    r = L'\n';
		} else if(ep[1] == L'\\') {
		    r = L'\\';
		} else {
		    memmove(ep, ep + 2, (len -= 2) * sizeof(*ep));
		    ep--;
		    continue;
		}
		memmove(ep, ep + 1, --len * sizeof(*ep));
		*ep = r;
	    }
	}
	*ep = L'\0';
	addtobuf(ret, swcsdup(p));
	p = p2;
    } while(p2 != NULL);
    addtobuf(ret, NULL);
    return(ret);
}

static void sendeoc(struct socket *sk)
{
    sockqueue(sk, "\n", 1);
}

static void sendadc1(struct socket *sk, int sep, wchar_t *arg)
{
    char *mbsbuf;
    wchar_t *buf;
    size_t bufsize, bufdata;
    
    buf = NULL;
    bufsize = bufdata = 0;
    if(sep)
	addtobuf(buf, L' ');
    for(; *arg != L'\0'; arg++) {
	if(*arg == L' ')
	    bufcat(buf, L"\\s", 2);
	else if(*arg == L'\n')
	    bufcat(buf, L"\\n", 2);
	else if(*arg == L'\\')
	    bufcat(buf, L"\\\\", 2);
	else
	    addtobuf(buf, *arg);
    }
    addtobuf(buf, L'\0');
    mbsbuf = icwcstombs(buf, "utf-8");
    sockqueue(sk, mbsbuf, strlen(mbsbuf));
    free(mbsbuf);
}

static void sendadc(struct socket *sk, int sep, ...)
{
    int i;
    va_list args;
    wchar_t *arg;
    wchar_t *type, *buf;
    
    va_start(args, sep);
    for(i = 0; (arg = va_arg(args, wchar_t *)) != NULL; i++) {
	if(arg == eoc) {
	    sendeoc(sk);
	} else if(arg == ns) {
	    sep = 0;
	} else if(arg == fmt) {
	    type = va_arg(args, wchar_t *);
	    if(!wcscmp(type, L"i")) {
		buf = swprintf2(L"%i", va_arg(args, int));
	    } else if(!wcscmp(type, L"mi")) {
		buf = swprintf2(L"%ji", va_arg(args, intmax_t));
	    }
	    sendadc1(sk, sep, buf);
	    free(buf);
	    sep = 1;
	} else {
	    sendadc1(sk, sep, arg);
	    sep = 1;
	}
    }
    va_end(args);
}

static wchar_t *findkv(wchar_t **argv, wchar_t *name)
{
    while(*argv != NULL) {
	if(!wcsncmp(*argv, name, 2))
	    return((*argv) + 2);
    }
    return(NULL);
}

static struct qcmd *newqcmd(struct qcmdqueue *queue, wchar_t **args)
{
    struct qcmd *new;
    
    new = smalloc(sizeof(*new));
    new->next = NULL;
    new->args = args;
    if(queue->l == NULL)
	queue->f = new;
    else
	queue->l->next = new;
    queue->l = new;
    queue->size++;
    return(new);
}

static struct qcmd *ulqcmd(struct qcmdqueue *queue)
{
    struct qcmd *ret;
    
    if((ret = queue->f) == NULL)
	return(NULL);
    if((queue->f = ret->next) == NULL)
	queue->l = NULL;
    queue->size--;
    return(ret);
}

static void freeqcmd(struct qcmd *qcmd)
{
    freeparr(qcmd->args);
    free(qcmd);
}

static void sendinf(struct fnetnode *fn)
{
    struct adchub *hub = fn->data;
    struct socket *sk = hub->sk;
    struct sockaddr_in *a4;
    socklen_t alen;
    
    sendadc(sk, 0, L"BINF", hub->sid, NULL);
    sendadc(sk, 1, L"PD", ns, privid, L"ID", ns, cid, NULL);
    sendadc(sk, 1, L"VEDolda ", ns, icsmbstowcs(VERSION, "us-ascii", NULL), NULL);
    sendadc(sk, 1, L"NI", ns, fn->mynick, NULL);
    sendadc(sk, 1, L"SS", ns, fmt, L"mi", (intmax_t)sharesize, L"SF", ns, fmt, L"i", sharedfiles, NULL);
    if(sk->family == AF_INET)
	sendadc(sk, 1, L"I40.0.0.0", NULL);
    else if(sk->family == AF_INET6)
	sendadc(sk, 1, L"I6::", NULL);
    sendadc(sk, 1, L"SL", ns, fmt, L"i", confgetint("transfer", "slot"), NULL);
    if(tcpsock != NULL) {
	if((sk->family == AF_INET) && !sockgetremotename(udpsock, (struct sockaddr **)&a4, &alen)) {
	    sendadc(sk, 1, L"U4", ns, fmt, L"i", ntohs(a4->sin_port), NULL);
	    free(a4);
	}
    }
    sendadc(sk, 1, eoc, NULL);
}

#define ADC_CMDFN(name) static void name(struct fnetnode *fn, wchar_t *command, wchar_t *sender, int argc, wchar_t **argv)
#ifdef __GNUC__
#define UNUSED __attribute__ ((unused))
#else
#define UNUSED
#endif
#define ADC_CMDCOM \
	struct adchub *hub UNUSED = fn->data; \
	struct socket *sk UNUSED = hub->sk;

ADC_CMDFN(cmd_sup)
{
    ADC_CMDCOM;
    int i, o, f;
    
    for(i = 1; i < argc; i++) {
	if(wcslen(argv[i]) < 3)
	    continue;
	for(o = 0, f = 0; hub->sup[o]; o++) {
	    if(!wcscmp(argv[i] + 2, hub->sup[o])) {
		f = 1;
		break;
	    }
	}
	if(!wcsncmp(argv[i], L"AD", 2)) {
	    if(f)
		continue;
	    hub->sup = srealloc(hub->sup, sizeof(*(hub->sup)) * (o + 1));
	    hub->sup[o] = swcsdup(argv[i] + 2);
	} else if(!wcsncmp(argv[i], L"RM", 2)) {
	    if(!f)
		continue;
	    free(hub->sup[o]);
	    memmove(hub->sup[o], hub->sup[o + 1], parrlen(hub->sup) - o);
	}
    }
}

ADC_CMDFN(cmd_sid)
{
    ADC_CMDCOM;
    
    if(hub->sid != NULL)
	free(hub->sid);
    hub->sid = swcsdup(argv[1]);
    if(hub->state == ADC_PROTOCOL) {
	hub->state = ADC_IDENTIFY;
	sendinf(fn);
    }
}

ADC_CMDFN(cmd_inf)
{
    ADC_CMDCOM;
    wchar_t *p;
    
    if(sender == NULL) {
	if((p = findkv(argv, L"NI")) != NULL)
	    fnetsetname(fn, p);
    }
}

static struct command hubcmds[] = {
    {L"SUP", 1, 0, 0, cmd_sup},
    {L"SID", 2, 0, 0, cmd_sid},
    {L"INF", 1, 0, 0, cmd_inf},
    {NULL, 0, 0, 0, NULL}
};

static void dispatch(struct qcmd *qcmd, struct fnetnode *fn)
{
    struct command *cmd;
    int argc;
    wchar_t *cmdnm, *sender, **argv;
    
    if((argc = parrlen(argv = qcmd->args)) < 1)
	return;
    cmdnm = *(argv++);
    argc--;
    if(wcslen(cmdnm) < 2)
	return;
    sender = NULL;
    if((*cmdnm == L'B') || (*cmdnm == L'F')) {
	if(argc < 1)
	    return;
	sender = *(argv++);
	argc--;
    } else if((*cmdnm == L'D') || (*cmdnm == L'E')) {
	if(argc < 2)
	    return;
	sender = *argv;
	argv += 2;
	argc -= 2;
    }
    for(cmd = hubcmds; cmd->func != NULL; cmd++) {
	if(!wcscmp(cmd->name, qcmd->args[0] + 1)) {
	    if(argc < cmd->minargs)
		return;
	    cmd->func(fn, cmdnm, sender, argc, argv);
	    return;
	}
    }
    flog(LOG_DEBUG, "unknown adc command: %ls", qcmd->args[0]);
}

static void peeraccept(struct socket *sk, struct socket *newsk, void *uudata)
{
}

static void udpread(struct socket *sk, void *uudata)
{
}

static void hubread(struct socket *sk, struct fnetnode *fn)
{
    int ret;
    struct adchub *hub;
    char *newbuf, *p1, *p2;
    wchar_t *p;
    size_t datalen, cblen;
    
    hub = fn->data;
    if((newbuf = sockgetinbuf(sk, &datalen)) == NULL)
	return;
    if(hub->inbufdata > 1024)
	hub->inbufdata = 0;
    bufcat(hub->inbuf, newbuf, datalen);
    free(newbuf);
    /* Memory eating protection */
    if(hub->cbdata > 65536)
	hub->cbdata = 0;
    while(hub->inbufdata > 0) {
	if(hub->cbdata == hub->cbsize)
	    sizebuf2(hub->cb, hub->cbdata + datalen, 1);
	p1 = hub->inbuf;
	p2 = (char *)(hub->cb + hub->cbdata);
	cblen = sizeof(*(hub->cb)) * (hub->cbsize - hub->cbdata);
	ret = iconv(hub->ich, &p1, &hub->inbufdata, &p2, &cblen);
	memmove(hub->inbuf, p1, hub->inbufdata);
	if(((p2 - ((char *)hub->cb)) % sizeof(*hub->cb)) != 0) {
	    flog(LOG_CRIT, "Spotted a dismembered wchar_t!");
	    abort();
	}
	hub->cbdata = hub->cbsize - (cblen / sizeof(*(hub->cb)));
	if(ret < 0) {
	    if(errno == EILSEQ) {
		flog(LOG_DEBUG, "adc fnetnode %i sent illegal utf-8 sequence", fn->id);
		killfnetnode(fn);
		return;
	    } else if(errno == EINVAL) {
		break;
	    } else if(errno == E2BIG) {
		/* continue; */
	    } else {
		flog(LOG_WARNING, "bug? iconv returned unexpected error: %s", strerror(errno));
		return;
	    }
	}
    }
    while((p = wmemchr(hub->cb, L'\n', hub->cbdata)) != NULL) {
	*(p++) = L'\0';
	newqcmd(&hub->queue, parseadc(hub->cb));
	memmove(hub->cb, p, (hub->cbdata -= (p - hub->cb)) * sizeof(*(hub->cb)));
    }
}

static void huberr(struct socket *sk, int err, struct fnetnode *fn)
{
    killfnetnode(fn);
}

static void hubconnect(struct fnetnode *fn, struct socket *sk)
{
    struct adchub *hub;
    
    sk->readcb = (void (*)(struct socket *, void *))hubread;
    sk->errcb = (void (*)(struct socket *, int, void *))huberr;
    sk->data = fn;
    
    hub = smalloc(sizeof(*hub));
    memset(hub, 0, sizeof(*hub));
    getsock(hub->sk = sk);
    if((hub->ich = iconv_open("wchar_t", "utf-8")) == (iconv_t)-1) {
	flog(LOG_CRIT, "iconv cannot handle UTF-8: %s", strerror(errno));
	killfnetnode(fn);
	return;
    }
    fn->data = hub;
    sendadc(sk, 0, L"HSUP", L"ADBASE", L"ADTIGR", eoc, NULL);
}

static void hubdestroy(struct fnetnode *fn)
{
    struct adchub *hub;
    
    hub = fn->data;
    iconv_close(hub->ich);
    if(hub->inbuf != NULL)
	free(hub->inbuf);
    if(hub->sup != NULL)
	freeparr(hub->sup);
    free(hub);
}

static void hubkill(struct fnetnode *fn)
{
    struct adchub *hub;
    
    hub = fn->data;
    hub->sk->close = 1;
}

static int hubsetnick(struct fnetnode *fn, wchar_t *newnick)
{
    return(0);
}

static int hubreqconn(struct fnetpeer *peer)
{
    return(0);
}

static struct fnet adcnet_store = {
    .connect = hubconnect,
    .destroy = hubdestroy,
    .kill = hubkill,
    .setnick = hubsetnick,
    .reqconn = hubreqconn,
    .name = L"adc"
};

static struct fnet *adcnet = &adcnet_store;

static int run(void)
{
    int ret;
    struct fnetnode *fn, *nextfn;
    struct adchub *hub;
    struct qcmd *qcmd;
    
    ret = 0;
    for(fn = fnetnodes; fn != NULL; fn = nextfn) {
	nextfn = fn->next;
	if(fn->fnet != adcnet)
	    continue;
	if((hub = fn->data) == NULL)
	    continue;
	if((qcmd = ulqcmd(&hub->queue)) != NULL) {
	    if((hub->sk != NULL) && (hub->sk->state == SOCK_EST))
		dispatch(qcmd, fn);
	    freeqcmd(qcmd);
	    ret = 1;
	    break;
	}
    }
    return(ret);
}

static void preinit(int hup)
{
    if(hup)
	return;
    regfnet(adcnet);
}

static void makepid(char *idbuf)
{
    int i;
    int fd, ret;
    
    i = 0;
    if((fd = open("/dev/urandom", O_RDONLY)) >= 0) {
	for(i = 0; i < 24; i += ret) {
	    if((ret = read(fd, idbuf + i, 24 - i)) <= 0) {
		flog(LOG_WARNING, "could not read random data from /dev/urandom for ADC PID: %s", (errno == 0)?"EOF":strerror(errno));
		break;
	    }
	}
	close(fd);
    } else {
	flog(LOG_WARNING, "could not open /dev/urandom: %s", strerror(errno));
    }
    if(i != 24) {
	for(i = 0; i < sizeof(idbuf); i++)
	    idbuf[i] = rand() % 256;
    }
}

static int updateudpport(struct configvar *var, void *uudata)
{
    struct sockaddr_in addr;
    struct socket *newsock;
    
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(var->val.num);
    if((newsock = netcsdgram((struct sockaddr *)&addr, sizeof(addr))) == NULL)
    {
	flog(LOG_WARNING, "could not create new DC UDP socket, reverting to old: %s", strerror(errno));
	return(0);
    }
    newsock->readcb = udpread;
    if(udpsock != NULL)
	putsock(udpsock);
    udpsock = newsock;
    return(0);
}

static int updatetcpport(struct configvar *var, void *uudata)
{
    struct sockaddr_in addr;
    struct socket *newsock;
    
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(var->val.num);
    if((newsock = netcslisten(SOCK_STREAM, (struct sockaddr *)&addr, sizeof(addr), peeraccept, NULL)) == NULL)
	flog(LOG_INFO, "could not listen to a remote address, going into passive mode");
    if(tcpsock != NULL)
	putsock(tcpsock);
    tcpsock = newsock;
    return(0);
}

static int init(int hup)
{
    char idbuf[24], *id32;
    struct tigerhash th;
    struct sockaddr_in addr;
    
    if(!hup) {
	eoc = swcsdup(L"");
	ns = swcsdup(L"");
	fmt = swcsdup(L"");
	
	if((privid = fetchvar("adc.pid", NULL)) == NULL) {
	    makepid(idbuf);
	    id32 = base32encode(idbuf, sizeof(idbuf));
	    id32[39] = 0;
	    privid = icmbstowcs(id32, "us-ascii");
	    free(id32);
	    storevar("adc.pid", privid, sizeof(*privid) * (wcslen(privid) + 1));
	}
	
	id32 = base32decode(icswcstombs(privid, "us-ascii", NULL), NULL);
	inittiger(&th);
	dotiger(&th, id32, 24);
	synctiger(&th);
	free(id32);
	restiger(&th, idbuf);
	id32 = base32encode(idbuf, sizeof(idbuf));
	id32[39] = 0;
	cid = icmbstowcs(id32, "us-ascii");
	free(id32);
	
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(confgetint("adc", "udpport"));
	if((udpsock = netcsdgram((struct sockaddr *)&addr, sizeof(addr))) == NULL) {
	    flog(LOG_CRIT, "could not create ADC UDP socket: %s", strerror(errno));
	    return(1);
	}
	udpsock->readcb = udpread;
	addr.sin_port = htons(confgetint("adc", "tcpport"));
	if((tcpsock = netcslisten(SOCK_STREAM, (struct sockaddr *)&addr, sizeof(addr), peeraccept, NULL)) == NULL) {
	    flog(LOG_CRIT, "could not create ADC TCP socket: %s", strerror(errno));
	    return(1);
	}
	CBREG(confgetvar("adc", "udpport"), conf_update, updateudpport, NULL, NULL);
	CBREG(confgetvar("adc", "tcpport"), conf_update, updatetcpport, NULL, NULL);
	CBREG(confgetvar("net", "mode"), conf_update, updatetcpport, NULL, NULL);
    }
    return(0);
}

static void terminate(void)
{
    
}

static struct configvar myvars[] = {
    /** Specifies a specific UDP port to use for ADC search
     * results. If left unspecified, a port is allocated
     * dynamically. Useful for NAT routers (see also the
     * net.visibleipv4 address for those cases). */
    {CONF_VAR_INT, "udpport", {.num = 0}},
    /** Specifies a specific TCP port to use for ADC peer
     * connections. If left unspecified, a port is allocated
     * dynamically. Useful for NAT routers (see also the
     * net.visibleipv4 address for those cases). */
    {CONF_VAR_INT, "tcpport", {.num = 0}},
    {CONF_VAR_END}
};

static struct module me = {
    .conf = {
	.vars = myvars
    },
    .preinit = preinit,
    .init = init,
    .run = run,
    .terminate = terminate,
    .name = "adc"
};

MODULE(me)