+++ /dev/null
-/*
- * citmail.c v4.0
- *
- * This program may be used as a local mail delivery agent, which will allow
- * all Citadel users to receive Internet e-mail. To enable this functionality,
- * you must tell sendmail, smail, or whatever mailer you are using, that this
- * program is your local mail delivery agent. This program is a direct
- * replacement for lmail, deliver, or whatever.
- *
- * Usage:
- *
- * citmail <recipient> - Deliver a message
- * citmail -t <recipient> - Address test mode (will not deliver)
- * citmail -i - Run as an SMTP daemon (typically from inetd)
- *
- */
-
-#include "sysdep.h"
-#include <stdlib.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <ctype.h>
-#include <string.h>
-#include <time.h>
-#include <pwd.h>
-#include <errno.h>
-#include <syslog.h>
-#include "citadel.h"
-
-#define LOCAL 0
-#define REMOTE 1
-#define UUCP 2
-#define CCITADEL 3
-
-#undef tolower
-#define tolower(x) isupper(x) ? (x+'a'-'A') : x
-
-char *monthdesc[] = { "Jan","Feb","Mar","Apr","May","Jun",
- "Jul","Aug","Sep","Oct","Nov","Dec" };
-
-
-
-void LoadInternetConfig();
-void get_config();
-int IsHostLocal();
-struct config config;
-
-char ALIASES[128];
-char CIT86NET[128];
-char SENDMAIL[128];
-char FALLBACK[128];
-char GW_DOMAIN[128];
-char TABLEFILE[128];
-char OUTGOING_FQDN[128];
-int RUN_NETPROC = 1;
-
-int struncmp(lstr,rstr,l)
-char lstr[],rstr[]; {
- int pos = 0;
- char lc,rc;
- while (1) {
- if (pos==l) return(0);
- lc=tolower(lstr[pos]);
- rc=tolower(rstr[pos]);
- if ((lc==0)&&(rc==0)) return(0);
- if (lc<rc) return(-1);
- if (lc>rc) return(1);
- pos=pos+1;
- }
- }
-
-long conv_date(sdbuf)
-char sdbuf[]; {
- int a,b,cpos,tend,tval;
- long now;
- struct tm *tmbuf;
- char dbuf[128];
-
- strcpy(dbuf,sdbuf);
- time(&now);
- tmbuf = (struct tm *)localtime(&now);
-
- /* get rid of + or - timezone mods */
- for (a=0; a<strlen(dbuf); ++a)
- if ((dbuf[a]=='+')||(dbuf[a]=='-'))
- do {
- strcpy(&dbuf[a],&dbuf[a+1]);
- } while ((dbuf[a]!=32)&&(dbuf[a]!=0));
-
- /* try and extract the time by looking for colons */
- cpos = (-1);
- for (a=strlen(dbuf); a>=0; --a)
- if ((dbuf[a]==':')&&(atoi(&dbuf[a-1])!=0)) cpos=a;
- if (cpos>=0) {
- cpos = cpos - 2;
- tend = strlen(dbuf);
- for (a=tend; a>=cpos; --a) if (dbuf[a]==' ') tend=a;
-
- tmbuf->tm_hour = atoi(&dbuf[cpos]);
- tmbuf->tm_min = atoi(&dbuf[cpos+3]);
- tmbuf->tm_sec = atoi(&dbuf[cpos+6]);
-
- do {
- strcpy(&dbuf[cpos],&dbuf[cpos+1]);
- } while ((dbuf[cpos]!=32)&&(dbuf[cpos]!=0));
- }
-
- /* next try to extract a month */
-
- tval = (-1);
- for (a=0; a<strlen(dbuf); ++a)
- for (b=0; b<12; ++b)
- if (!strncmp(&dbuf[a],monthdesc[b],3)) {
- tval = b;
- cpos = a;
- }
- if (tval >= 0) {
- tmbuf->tm_mon = tval;
- strcpy(&dbuf[cpos],&dbuf[cpos+3]);
- }
-
- /* now the year */
-
- for (a=0; a<strlen(dbuf); ++a)
- if ((atoi(&dbuf[a])>=1900) && (dbuf[a]!=32)) {
- tmbuf->tm_year = atoi(&dbuf[a]) - 1900;
- strcpy(&dbuf[a],&dbuf[a+4]);
- }
-
- /* whatever's left is the mday (hopefully) */
-
- for (a=0; a<strlen(dbuf); ++a)
- if ((dbuf[a]!=32)&&(atoi(&dbuf[a])>=1)&&(atoi(&dbuf[a])<=31)
- && ( (a==0)||(dbuf[a-1]==' ') ) ) {
- tmbuf->tm_mday = atoi(&dbuf[a]);
- strcpy(&dbuf[a],&dbuf[a+2]);
- }
-
- return((long)mktime(tmbuf));
- }
-
-
-#ifdef NO_STRERROR
-/*
- * replacement strerror() for systems that don't have it
- */
-char *strerror(e)
-int e; {
- static char buf[32];
-
- sprintf(buf,"errno = %d",e);
- return(buf);
- }
-#endif
-
-int haschar(st,ch)
-char st[];
-int ch; {
- int a,b;
- b=0;
- for (a=0; a<strlen(st); ++a) if (st[a]==ch) ++b;
- return(b);
- }
-
-void strip_trailing_whitespace(buf)
-char buf[]; {
- while(isspace(buf[strlen(buf)-1]))
- buf[strlen(buf)-1]=0;
- }
-
-int islocalok(char recp[]) {
-
- struct usersupp ust;
- long lookfor;
- char a_recp[128];
- int found_closest_match = 0;
- int a,us;
- strcpy(a_recp,recp);
- for (a=0; a<strlen(a_recp); ++a)
- if (a_recp[a]=='_') a_recp[a]=32;
- lookfor = (-1L); if (!struncmp(recp,"cit",3)) lookfor=atol(&recp[3]);
- us=open("/appl/citadel/usersupp",O_RDONLY);
- if (us>=0) {
- while(read(us,&ust,sizeof(struct usersupp))>0) {
- if (lookfor == ust.usernum) {
- strcpy(recp,ust.fullname);
- close(us);
- return(2);
- }
- if (!strucmp(ust.fullname,a_recp)) {
- strcpy(recp,ust.fullname);
- close(us);
- return(3);
- }
- if (!struncmp(ust.fullname,a_recp,strlen(a_recp))) {
- strcpy(recp,ust.fullname);
- found_closest_match = 1;
- }
- }
- close(us);
- }
- if (getpwnam(recp)!=NULL) return(1);
- if (found_closest_match) return(3);
- return(0);
- }
-
-/* strip leading and trailing spaces */
-void striplt(buf)
-char buf[]; {
- while ( (strlen(buf)>0) && (buf[0]==32) ) strcpy(buf,&buf[1]);
- while (buf[strlen(buf)-1] == 32) buf[strlen(buf)-1] = 0;
- }
-
-
-/*
- * Check to see if a given FQDN really maps to a Citadel network node
- */
-void host_alias(char host[]) {
-
- int a;
-
- /* What name is the local host known by? */
- /* if (!strucmp(host, config.c_fqdn)) { */
- if (IsHostLocal(host)) {
- strcpy(host, config.c_nodename);
- return;
- }
-
- /* Other hosts in the gateway domain? */
- for (a=0; a<strlen(host); ++a) {
- if ((host[a]=='.') && (!strucmp(&host[a+1], GW_DOMAIN))) {
- host[a] = 0;
- for (a=0; a<strlen(host); ++a) {
- if (host[a]=='.') host[a] = 0;
- }
- return;
- }
- }
-
- /* Otherwise, do nothing... */
- }
-
-
-
-/*
- * Split an RFC822-style address into userid, host, and full name
- */
-void process_rfc822_addr(rfc822,user,node,name)
-char rfc822[];
-char user[];
-char node[];
-char name[]; {
- int a;
-
- /* extract full name - first, it's From minus <userid> */
- strcpy(name,rfc822);
- for (a=0; a<strlen(name); ++a) if (name[a]=='<') {
- do {
- strcpy(&name[a],&name[a+1]);
- } while ( (strlen(name) > 0) && (name[a]!='>') );
- strcpy(&name[a],&name[a+1]);
- }
-
- /* strip anything to the left of a bang */
- while ( (strlen(name)>0) && (haschar(name,'!')>0) )
- strcpy(name,&name[1]);
-
- /* and anything to the right of a @ or % */
- for (a=0; a<strlen(name); ++a) {
- if (name[a]=='@') name[a]=0;
- if (name[a]=='%') name[a]=0;
- }
-
- /* but if there are parentheses, that changes the rules... */
- if ( (haschar(rfc822,'(') == 1) && (haschar(rfc822,')') == 1) ) {
- strcpy(name,rfc822);
- while ( (strlen(name) > 0) && (name[0]!='(') ) {
- strcpy(&name[0],&name[1]);
- }
- strcpy(&name[0],&name[1]);
- for (a=0; a<strlen(name); ++a)
- if (name[a]==')') name[a]=0;
- }
-
- /* but if there are a set of quotes, that supersedes everything */
- if (haschar(rfc822,34)==2) {
- strcpy(name,rfc822);
- while ( (strlen(name) > 0) && (name[0]!=34) ) {
- strcpy(&name[0],&name[1]);
- }
- strcpy(&name[0],&name[1]);
- for (a=0; a<strlen(name); ++a)
- if (name[a]==34) name[a]=0;
- }
-
- /* extract user id */
- strcpy(user,rfc822);
-
- /* first get rid of anything in parens */
- for (a=0; a<strlen(user); ++a) if (user[a]=='(') {
- do {
- strcpy(&user[a],&user[a+1]);
- } while ( (strlen(user) > 0) && (user[a]!=')') );
- strcpy(&user[a],&user[a+1]);
- }
-
- /* if there's a set of angle brackets, strip it down to that */
- if ( (haschar(user,'<') == 1) && (haschar(user,'>') == 1) ) {
- while ( (strlen(user) > 0) && (user[0]!='<') ) {
- strcpy(&user[0],&user[1]);
- }
- strcpy(&user[0],&user[1]);
- for (a=0; a<strlen(user); ++a)
- if (user[a]=='>') user[a]=0;
- }
-
- /* strip anything to the left of a bang */
- while ( (strlen(user)>0) && (haschar(user,'!')>0) )
- strcpy(user,&user[1]);
-
- /* and anything to the right of a @ or % */
- for (a=0; a<strlen(user); ++a) {
- if (user[a]=='@') user[a]=0;
- if (user[a]=='%') user[a]=0;
- }
-
-
-
- /* extract node name */
- strcpy(node, rfc822);
-
- /* first get rid of anything in parens */
- for (a=0; a<strlen(node); ++a) if (node[a]=='(') {
- do {
- strcpy(&node[a],&node[a+1]);
- } while ( (strlen(node) > 0) && (node[a]!=')') );
- strcpy(&node[a],&node[a+1]);
- }
-
- /* if there's a set of angle brackets, strip it down to that */
- if ( (haschar(node,'<') == 1) && (haschar(node,'>') == 1) ) {
- while ( (strlen(node) > 0) && (node[0]!='<') ) {
- strcpy(&node[0],&node[1]);
- }
- strcpy(&node[0],&node[1]);
- for (a=0; a<strlen(node); ++a)
- if (node[a]=='>') node[a]=0;
- }
-
- /* strip anything to the left of a @ */
- while ( (strlen(node)>0) && (haschar(node,'@')>0) )
- strcpy(node,&node[1]);
-
- /* strip anything to the left of a % */
- while ( (strlen(node)>0) && (haschar(node,'%')>0) )
- strcpy(node,&node[1]);
-
- /* reduce multiple system bang paths to node!user */
- while ( (strlen(node)>0) && (haschar(node,'!')>1) )
- strcpy(node,&node[1]);
-
- /* now get rid of the user portion of a node!user string */
- for (a=0; a<strlen(node); ++a) if (node[a]=='!') node[a]=0;
-
-
-
- /* strip leading and trailing spaces in all strings */
- striplt(user);
- striplt(node);
- striplt(name);
- }
-
-/*
- * Copy line by line, ending at EOF or a "."
- */
-void loopcopy(FILE *to, FILE *from) {
- char buf[1024];
- char *r;
-
- while (1) {
- r = fgets(buf, sizeof(buf), from);
- if (r == NULL) return;
- strip_trailing_whitespace(buf);
- if (!strcmp(buf, ".")) return;
- fprintf(to, "%s\n", buf);
- }
- }
-
-
-/*
- * pipe message through netproc
- */
-void do_citmail(char recp[], int dtype) {
-
- long now;
- FILE *temp;
- int a;
- char buf[128];
- char from[512];
- char userbuf[256];
- char frombuf[256];
- char nodebuf[256];
- char destsys[256];
- char subject[256];
-
-
- if (dtype==REMOTE) {
-
- /* get the Citadel node name out of the path */
- strncpy(destsys, recp, sizeof(destsys) );
- for (a=0; a<strlen(destsys); ++a) {
- if ((destsys[a]=='!')||(destsys[a]=='.')) {
- destsys[a]=0;
- }
- }
-
- /* chop the system name out, so we're left with a user */
- while (haschar(recp,'!')) strcpy(recp,&recp[1]);
-
- /* now convert underscores to spaces */
- for (a=0; a<strlen(recp); ++a) if (recp[a]=='_') recp[a]=' ';
-
- }
-
- time(&now);
- sprintf(from, "postmaster@%s", config.c_nodename);
-
- sprintf(buf, "./network/spoolin/citmail.%d", getpid());
- temp = fopen(buf,"w");
-
- putc(255,temp); putc(MES_NORMAL,temp); putc(1,temp);
- strcpy(subject,"");
- strcpy(nodebuf, config.c_nodename);
- do {
- if (fgets(buf,128,stdin) == NULL) strcpy(buf, ".");
- strip_trailing_whitespace(buf);
-
- if (!strncmp(buf,"Subject: ",9)) strcpy(subject,&buf[9]);
- if (!strncmp(buf,"Date: ",6)) now = conv_date(&buf[6]);
- if (!strncmp(buf,"From: ",6)) strcpy(from, &buf[6]);
- } while ( (strcmp(buf, ".")) && (strcmp(buf, "")) );
-
- process_rfc822_addr(from, userbuf, nodebuf, frombuf);
-
- /* now convert it to Citadel format */
- fprintf(temp,"P%s@%s%c", userbuf, nodebuf, 0);
- fprintf(temp,"E%s%c", userbuf, 0);
- fprintf(temp,"T%ld%c", now, 0);
- fprintf(temp,"A%s%c", frombuf, 0);
- fprintf(temp,"OMail%c", 0);
- fprintf(temp,"N%s%c", nodebuf, 0);
- if (dtype==REMOTE) {
- fprintf(temp,"D%s%c", destsys, 0);
- }
- fprintf(temp,"R%s%c", recp, 0);
- if (strlen(subject)>0) {
- fprintf(temp,"U%s%c", subject, 0);
- }
- putc('M',temp);
- if (strcmp(buf, ".")) loopcopy(temp, stdin);
- putc(0,temp);
- fclose(temp);
- }
-
-void do_roommail(recp) /* pipe public message through netproc */
-char recp[]; {
- long now;
- FILE *temp;
- int a;
- char buf[128],userbuf[128],frombuf[128],nodebuf[128];
- char subject[128], from[256];
-
- strcpy(subject,"");
- sprintf(from, "postmaster@%s", config.c_nodename);
- strcpy(recp,&recp[5]);
- for (a=0; a<strlen(recp); ++a) if (recp[a]=='_') recp[a]=32;
- time(&now);
-
-
- sprintf(buf,"./network/spoolin/citmail.%d",getpid());
- temp = fopen(buf,"w");
-
- putc(255,temp); putc(MES_NORMAL,temp); putc(1,temp);
- strcpy(frombuf,"Internet Mail Gateway");
- strcpy(nodebuf, config.c_nodename);
- do {
- if (fgets(buf,128,stdin) == NULL) strcpy(buf, ".");
- strip_trailing_whitespace(buf);
-
- if (!strncmp(buf,"Subject: ",9)) strcpy(subject,&buf[9]);
- if (!strncmp(buf,"Date: ",6)) now = conv_date(&buf[6]);
- if (!strncmp(buf,"From: ",6)) strcpy(from, &buf[6]);
- } while ( (strcmp(buf, ".")) && (strcmp(buf, "")) );
-
- process_rfc822_addr(from, userbuf, nodebuf, frombuf);
-
- fprintf(temp,"P%s@%s",userbuf,nodebuf); putc(0,temp);
- fprintf(temp,"T%ld",now); putc(0,temp);
- fprintf(temp,"A%s",frombuf); putc(0,temp);
- fprintf(temp,"O%s",recp); putc(0,temp);
- fprintf(temp,"N%s",nodebuf); putc(0,temp);
- if (strlen(subject)>0) {
- fprintf(temp,"U%s",subject); putc(0,temp);
- }
- putc('M',temp);
- if (strcmp(buf, ".")) loopcopy(temp, stdin);
- putc(0,temp);
- fclose(temp);
- }
-
-void do_uudecode(target)
-char *target; {
- static char buf[1024];
- FILE *fp;
-
- sprintf(buf,"cd %s; uudecode",target);
-
- fp=popen(buf,"w");
- if (fp==NULL) return;
- while (fgets(buf,1024,stdin)!=NULL) {
- fprintf(fp,"%s",buf);
- }
- pclose(fp);
-
- }
-
-void do_fallback(recp)
-char recp[]; {
- static char buf[1024];
- FILE *fp;
-
- sprintf(buf, FALLBACK, recp);
- fp=popen(buf,"w");
- if (fp==NULL) fp = popen("cat >/dev/null", "w");
- loopcopy(fp, stdin);
- pclose(fp);
- }
-
-int alias(name)
-char *name; {
- FILE *fp;
- int a;
- char abuf[256];
-
- fp=fopen(ALIASES,"r");
- if (fp==NULL) {
- syslog(LOG_ERR,"cannot open %s: %s",ALIASES,strerror(errno));
- return(2);
- }
-
- while (fgets(abuf,256,fp)!=NULL) {
- strip_trailing_whitespace(abuf);
- for (a=0; a<strlen(abuf); ++a) {
- if (abuf[a]==',') {
- abuf[a]=0;
- if (!strucmp(name,abuf)) {
- strcpy(name,&abuf[a+1]);
- }
- }
- }
- }
- fclose(fp);
- return(0);
- }
-
-
-void deliver(char recp[], int is_test, int deliver_to_ignet) {
-
- int b;
- b=islocalok(recp);
-
- /* various ways we can deliver mail... */
-
- if (deliver_to_ignet) {
- syslog(LOG_NOTICE,"to Citadel network user %s",recp);
- if (is_test == 0) do_citmail(recp, REMOTE);
- }
-
- else if (!strcmp(recp,"uudecode")) {
- syslog(LOG_NOTICE,"uudecoding to bit bucket directory");
- if (is_test == 0) do_uudecode(config.c_bucket_dir);
- }
-
- else if (!strcmp(recp,"cit86net")) {
- syslog(LOG_NOTICE,"uudecoding to Cit86net spool");
- if (is_test == 0) {
- do_uudecode(CIT86NET);
- system("exec ./BatchTranslate86");
- }
- }
-
- else if (!strcmp(recp,"null")) {
- syslog(LOG_NOTICE,"zapping nulled message");
- }
-
- else if (!struncmp(recp,"room_",5)) {
- syslog(LOG_NOTICE,"to room %s",recp);
- if (is_test == 0) do_roommail(recp);
- }
-
- else if (b==1) {
- syslog(LOG_NOTICE,"fallback mailer to user %s",recp);
- if (is_test == 0) do_fallback(recp);
- }
-
- else {
- /* Otherwise, the user is local (or an unknown name was specified, in
- * which case we let netproc handle the bounce)
- */
- syslog(LOG_NOTICE,"to Citadel user %s",recp);
- if (is_test == 0) do_citmail(recp, LOCAL);
- }
-
- }
-
-
-
-void main(argc,argv)
-int argc;
-char *argv[]; {
- int is_test = 0;
- int deliver_to_ignet = 0;
- int smtp = 0;
- static char recp[1024], buf[1024];
- static char user[1024], node[1024], name[1024];
- int a;
-
- openlog("citmail", LOG_PID, LOG_USER);
- get_config();
- LoadInternetConfig();
-
- if (!strcmp(argv[1],"-t")) {
- is_test = 1;
- syslog(LOG_NOTICE,"test mode - will not deliver");
- }
- if (!strcmp(argv[1], "-i")) {
- smtp = 1;
- syslog(LOG_NOTICE,"started as an SMTP daemon");
- }
-
-
- if (smtp) {
- strcpy(recp, "");
- }
- else if (is_test == 0) {
- strcpy(recp,argv[1]);
- }
- else {
- strcpy(recp,argv[2]);
- }
-
-
- if (smtp) {
- /*** SMTP delivery mode ***/
-
- printf("200 Citadel/UX SMTP gateway ready.\n");
-
- do {
- fflush(stdout);
- fflush(stderr);
- fgets(buf, 1024, stdin);
- while ( (strlen(buf)>0) && (buf[strlen(buf)-1]>0) && (buf[strlen(buf)-1]<32) ) {
- buf[strlen(buf)-1] = 0;
- }
-
- /* null-pad to allow some lazy compares */
- buf[strlen(buf)+1] = 0;
- buf[strlen(buf)+2] = 0;
- buf[strlen(buf)+3] = 0;
-
- if (!struncmp(buf, "QUIT", 4)) {
- printf("221 Later, dude.\n");
- }
- else if (!struncmp(buf, "HELP", 4)) {
- printf("214 You think _you_ need help?\n");
- }
- else if (!struncmp(buf, "HELO", 4)) {
- printf("250 Howdy ho, Mr. Hankey!\n");
- }
- else if (!struncmp(buf, "MAIL", 4)) {
- printf("250 Sure, whatever...\n");
- }
-
-
- else if (!struncmp(buf, "RCPT To: ", 9)) {
- if (strlen(recp) > 0) {
- printf("571 Multiple recipients not supported.\n");
- }
- else {
- strcpy(recp, &buf[9]);
- if (haschar(recp, ',')) {
- printf("571 Multiple recipients not supported.\n");
- strcpy(recp, "");
- }
- else {
- syslog(LOG_NOTICE,"recp: %s",recp);
- for (a=0; a<2; ++a) {
- alias(recp);
- }
-
- /* did we alias it back to a remote address? */
- if ( (haschar(recp,'%'))
- || (haschar(recp,'@'))
- || (haschar(recp,'!')) ) {
-
- process_rfc822_addr(recp, user, node, name);
- host_alias(node);
-
- /* If there are dots, it's an Internet host, so feed it
- * back to an external mail transport agent such as sendmail.
- */
- if (haschar(node, '.')) {
- printf("571 Away with thee, spammer!\n");
- strcpy(recp, "");
- }
-
- /* Otherwise, we're dealing with Citadel mail. */
- else {
- sprintf(recp, "%s!%s", node, user);
- deliver_to_ignet = 1;
- printf("250 IGnet recipient.\n");
- }
- }
- else {
- printf("250 Local recipient.\n");
- }
-
- }
-
- }
- }
-
-
-
- else if (!struncmp(buf, "RCPT", 4)) {
- printf("501 Only 'To:' commands are supported.\n");
- }
- else if (!struncmp(buf, "DATA", 4)) {
- if (strlen(recp) > 0) {
- printf("354 Sock it to me, baby...\n");
- fflush(stdout);
- deliver(recp, is_test, deliver_to_ignet);
- printf("250 Cool beans!\n");
- }
- else {
- printf("503 No recipient has been specified.\n");
- }
- }
- else {
- printf("500 Huh?\n");
- }
-
- } while (struncmp(buf,"QUIT",4));
- }
-
- else {
- /*** Non-SMTP delivery mode ***/
- syslog(LOG_NOTICE,"recp: %s",recp);
- for (a=0; a<2; ++a) {
- alias(recp);
- }
-
- /* did we alias it back to a remote address? */
- if ( (haschar(recp,'%'))
- || (haschar(recp,'@'))
- || (haschar(recp,'!')) ) {
-
- process_rfc822_addr(recp, user, node, name);
- host_alias(node);
-
- /* If there are dots, it's an Internet host, so feed it
- * back to an external mail transport agent such as sendmail.
- */
- if (haschar(node, '.')) {
- sprintf(buf, SENDMAIL, recp);
- system(buf);
- exit(0);
- }
-
- /* Otherwise, we're dealing with Citadel mail. */
- else {
- sprintf(recp, "%s!%s", node, user);
- deliver_to_ignet = 1;
- }
-
- }
-
- deliver(recp, is_test, deliver_to_ignet);
- }
-
- closelog();
- if (RUN_NETPROC) execlp("./netproc","netproc",NULL);
- exit(0);
- }
-
projects / citadel.git / blobdiff