Example #1
0
/**
 *
 * @param ccnl
 * @param content
 * @param content_len
 * @param sig
 * @param sig_len
 * @param callback function which should be called when crypto system returns
 *              for a new callback function you have to extend ccnl_crypto()!!!!
 * @return
 */
int
ccnl_crypto_verify(struct ccnl_relay_s *ccnl, char *content, int content_len,
        char *sig, int sig_len, char* callback, int sequnum)
{
    char *msg = 0;
    int len = 0, ret = 0;
    struct ccnl_buf_s *retbuf;
    //int plen;
    //unsigned char *buf;
    plen = 0;
    memset(buf,0,sizeof(buf));
    if(!ccnl->crypto_face) return ret;

    msg = (char *)ccnl_malloc(sizeof(char)*(content_len+sig_len)+3000);

    len = ccnl_crypto_create_ccnl_sign_verify_msg("verify", sequnum, content,
            content_len, sig, sig_len, msg, callback);

    if(len > CCNL_MAX_PACKET_SIZE){
        DEBUGMSG(DEBUG,"Ignored, packet size too large");
        return 0;
    }
    //send ccn_msg to crytoserver
    retbuf = ccnl_buf_new((char *)msg, len);
    ccnl_face_enqueue(ccnl, ccnl->crypto_face, retbuf);

    if(msg) ccnl_free(msg);
    return ret;
}
Example #2
0
void ccnl_interest_propagate(struct ccnl_relay_s *ccnl,
                             struct ccnl_interest_s *i)
{
    struct ccnl_forward_s *fwd;
    DEBUGMSG(99, "ccnl_interest_propagate\n");

    // CONFORM: "A node MUST implement some strategy rule, even if it is only to
    // transmit an Interest Message on all listed dest faces in sequence."
    // CCNL strategy: we forward on all FWD entries with a prefix match
    int forward_cnt = 0;
    for (fwd = ccnl->fib; fwd; fwd = fwd->next) {
        int rc = ccnl_prefix_cmp(fwd->prefix, NULL, i->prefix, CMP_LONGEST);
        DEBUGMSG(40, "  ccnl_interest_propagate, rc=%d/%d\n", rc,
                 fwd->prefix->compcnt);

        if (rc < fwd->prefix->compcnt) {
            continue;
        }

        DEBUGMSG(40, "  ccnl_interest_propagate, fwd==%p\n", (void *) fwd);

        // suppress forwarding to origin of interest, except wireless
        if (!i->from || fwd->face != i->from
            || (i->from->flags & CCNL_FACE_FLAGS_REFLECT)) {

            i->forwarded_over = fwd;
            fwd->face->stat.send_interest[i->retries]++;
            ccnl_get_timeval(&i->last_used);
            ccnl_face_enqueue(ccnl, fwd->face, buf_dup(i->pkt));
            ccnl_get_timeval(&fwd->last_used);
            forward_cnt++;
        }
    }

    if (forward_cnt == 0) {
        DEBUGMSG(40, "  ccnl_interest_propagate: using broadcast face!\n");
        ccnl->ifs[RIOT_TRANS_IDX].broadcast_face->stat.send_interest[i->retries]++;
        ccnl_get_timeval(&i->last_used);
        ccnl_face_enqueue(ccnl, ccnl->ifs[RIOT_TRANS_IDX].broadcast_face, buf_dup(i->pkt));
    }

    return;
}
Example #3
0
// deliver new content c to all clients with (loosely) matching interest,
// but only one copy per face
// returns: number of forwards
int ccnl_content_serve_pending(struct ccnl_relay_s *ccnl,
                               struct ccnl_content_s *c,
                               struct ccnl_face_s *from)
{
    struct ccnl_interest_s *i;
    struct ccnl_face_s *f;
    int cnt = 0;
    DEBUGMSG(99, "ccnl_content_serve_pending\n");

    for (f = ccnl->faces; f; f = f->next) {
        f->flags &= ~CCNL_FACE_FLAGS_SERVED;    // reply on a face only once
    }

    for (i = ccnl->pit; i;) {
        struct ccnl_pendint_s *pi;

        if (!ccnl_i_prefixof_c(i->prefix, i->ppkd, i->minsuffix, i->maxsuffix,
                               c)) {
            i = i->next;
            continue;
        }

        // CONFORM: "Data MUST only be transmitted in response to
        // an Interest that matches the Data."
        for (pi = i->pending; pi; pi = pi->next) {
            if (pi->face->flags & CCNL_FACE_FLAGS_SERVED) {
                continue;
            }

            if (pi->face == from) {
                // the existing pending interest is from the same face
                // as the newly arrived content is...no need to send content back
                DEBUGMSG(1, "  detected looping content, before loop could happen\n");
                continue;
            }

            pi->face->flags |= CCNL_FACE_FLAGS_SERVED;

            DEBUGMSG(6, "  forwarding content <%s>\n",
                     ccnl_prefix_to_path(c->name));
            pi->face->stat.send_content[c->served_cnt % CCNL_MAX_CONTENT_SERVED_STAT]++;
            ccnl_face_enqueue(ccnl, pi->face, buf_dup(c->pkt));

            c->served_cnt++;
            ccnl_get_timeval(&c->last_used);
            cnt++;
        }

        i = ccnl_interest_remove(ccnl, i);
    }

    return cnt;
}
Example #4
0
int
ccnl_mgmt_crypto(struct ccnl_relay_s *ccnl, char *type, unsigned char *buf, int buflen)
{

   struct ccnl_face_s *from;
   DEBUGMSG(DEBUG,"ccnl_crypto type: %s\n", type);

   if(!strcmp(type, "verify")){
      int seqnum = 0;
      int verified = ccnl_crypto_extract_verify_reply(&buf, &buflen, &seqnum);
      unsigned char *msg, *msg2;
      char cmd[500];
      int len = ccnl_crypto_extract_msg(&buf, &buflen, &msg), len2 = 0;
      struct ccnl_face_s *from;
      //DEBUGMSG(DEBUG,"VERIFIED: %d, MSG_LEN: %d\n", verified, len);

      int scope=3, aok=3, minsfx=0, maxsfx=CCNL_MAX_NAME_COMP, contlen;
      struct ccnl_buf_s *buf1 = 0, *nonce=0, *ppkd=0;
      struct ccnl_prefix_s *p = 0;
      struct ccnl_buf_s *msg2_buf;
      unsigned char *content = 0;

      msg2 = (char *) ccnl_malloc(sizeof(char) * len + 200);
      len2 = ccnl_ccnb_mkHeader(msg2,CCN_DTAG_NAME, CCN_TT_DTAG);
      memcpy(msg2+len2, msg, len);
      len2 +=len;
      msg2[len2++] = 0;

      from = ccnl->faces;
      while(from){
          if(from->faceid == seqnum)
              break;
          from = from->next;
      }

      buf1 = ccnl_ccnb_extract(&msg2, &len2, &scope, &aok, &minsfx,
                         &maxsfx, &p, &nonce, &ppkd, &content, &contlen);

      if (p->complen[2] < sizeof(cmd)) {
            memcpy(cmd, p->comp[2], p->complen[2]);
            cmd[p->complen[2]] = '\0';
      } else
            strcpy(cmd, "cmd-is-too-long-to-display");
      msg2_buf = ccnl_buf_new((char *)msg2, len2);
      ccnl_mgmt_handle(ccnl, msg2_buf, p, from, cmd, verified);
      ccnl_free(msg2_buf);
   }else if(!strcmp(type, "sign")){
      char *sig = (char *) ccnl_malloc(sizeof(char)* CCNL_MAX_PACKET_SIZE);
      unsigned char *out;
      unsigned char *msg;
      int siglen = 0, seqnum = 0, len, len1;
      struct ccnl_buf_s *retbuf;

      ccnl_crypto_extract_sign_reply(&buf, &buflen, sig, &siglen, &seqnum);

      len = ccnl_crypto_extract_msg(&buf, &buflen, &msg);
      out = (char *) ccnl_malloc(sizeof(unsigned char)*len + sizeof(unsigned char)*siglen + 4096);

      len1 = ccnl_ccnb_mkHeader(out, CCN_DTAG_CONTENTOBJ, CCN_TT_DTAG);   // content
      if(siglen > 0) len1 += ccnl_crypto_add_signature(out+len1, sig, siglen);

      memcpy(out+len1, msg, len);
      len1 +=len;

      out[len1++] = 0; // end-of-interest
      from = ccnl->faces;
      while(from){
          if(from->faceid == seqnum)
              break;
          from = from->next;
      }

      retbuf = ccnl_buf_new((char *)out, len1);
      if(seqnum >= 0){
          ccnl_face_enqueue(ccnl, from, retbuf);
      }else{
          struct ccnl_prefix_s *prefix_a = 0;
          struct ccnl_content_s *c = 0;
          struct ccnl_buf_s *nonce=0, *ppkd=0, *pkt = 0;
          unsigned char *content = 0;
          char *ht = (char *) ccnl_malloc(sizeof(char)*20);
          int contlen;
          pkt = ccnl_ccnb_extract(&out, &len1, 0, 0, 0, 0,
                                  &prefix_a, &nonce, &ppkd, &content, &contlen);

          if (!pkt) {
               DEBUGMSG(WARNING, " parsing error\n"); goto Done;
          }
          if (prefix_a) {
              //DEBUGMSG(DEBUG, "%s", prefix_a->comp);
              //ccnl_free(prefix_a);
          }
          //prefix_a = (struct ccnl_prefix_s *)ccnl_malloc(sizeof(struct ccnl_prefix_s));
          prefix_a->compcnt = 2;
          prefix_a->comp = (unsigned char **) ccnl_malloc(sizeof(unsigned char*)*2);
          prefix_a->comp[0] = "mgmt";
          sprintf(ht, "seqnum-%d", -seqnum);
          prefix_a->comp[1] = ht;
          prefix_a->complen = (int *) ccnl_malloc(sizeof(int)*2);
          prefix_a->complen[0] = strlen("mgmt");
          prefix_a->complen[1] = strlen(ht);
          c = ccnl_content_new(ccnl, CCNL_SUITE_CCNB, &pkt, &prefix_a, &ppkd,
                                content, contlen);
          if (!c) goto Done;

          ccnl_content_serve_pending(ccnl, c);
          ccnl_content_add2cache(ccnl, c);
      }
      Done:
      ccnl_free(out);
   }
   return 0;
}
Example #5
0
// deliver new content c to all clients with (loosely) matching interest,
// but only one copy per face
// returns: number of forwards
int
ccnl_content_serve_pending(struct ccnl_relay_s *ccnl, struct ccnl_content_s *c)
{
    struct ccnl_interest_s *i;
    struct ccnl_face_s *f;
    int cnt = 0;
    DEBUGMSG_CORE(TRACE, "ccnl_content_serve_pending\n");

    for (f = ccnl->faces; f; f = f->next){
                f->flags &= ~CCNL_FACE_FLAGS_SERVED; // reply on a face only once
    }
    for (i = ccnl->pit; i;) {
        struct ccnl_pendint_s *pi;
        if (!i->pkt->pfx)
            continue;

        switch (i->pkt->pfx->suite) {
#ifdef USE_SUITE_CCNB
        case CCNL_SUITE_CCNB:
            if (!ccnl_i_prefixof_c(i->pkt->pfx, i->pkt->s.ccnb.minsuffix,
                       i->pkt->s.ccnb.maxsuffix, c)) {
                // XX must also check i->ppkd
                i = i->next;
                continue;
            }
            break;
#endif
#ifdef USE_SUITE_CCNTLV
        case CCNL_SUITE_CCNTLV:
            if (ccnl_prefix_cmp(c->pkt->pfx, NULL, i->pkt->pfx, CMP_EXACT)) {
                // XX must also check keyid
                i = i->next;
                continue;
            }
            break;
#endif
#ifdef USE_SUITE_CISTLV
        case CCNL_SUITE_CISTLV:
            if (ccnl_prefix_cmp(c->pkt->pfx, NULL, i->pkt->pfx, CMP_EXACT)) {
                // XX must also check keyid
                i = i->next;
                continue;
            }
            break;
#endif
#ifdef USE_SUITE_IOTTLV
        case CCNL_SUITE_IOTTLV:
          if (ccnl_prefix_cmp(c->pkt->pfx, NULL, i->pkt->pfx, CMP_EXACT)) {
                // XX must also check keyid
                i = i->next;
                continue;
            }
            break;
#endif
#ifdef USE_SUITE_NDNTLV
        case CCNL_SUITE_NDNTLV:
            if (!ccnl_i_prefixof_c(i->pkt->pfx, i->pkt->s.ndntlv.minsuffix,
                       i->pkt->s.ndntlv.maxsuffix, c)) {
                // XX must also check i->ppkl,
                i = i->next;
                continue;
            }
            break;
#endif
        default:
            i = i->next;
            continue;
        }

        //Hook for add content to cache by callback:
        if(i && ! i->pending){
            DEBUGMSG_CORE(WARNING, "releasing interest 0x%p OK?\n", (void*)i);
            c->flags |= CCNL_CONTENT_FLAGS_STATIC;
            i = ccnl_interest_remove(ccnl, i);
            return 1;
        }

        // CONFORM: "Data MUST only be transmitted in response to
        // an Interest that matches the Data."
        for (pi = i->pending; pi; pi = pi->next) {
            if (pi->face->flags & CCNL_FACE_FLAGS_SERVED)
            continue;
            pi->face->flags |= CCNL_FACE_FLAGS_SERVED;
            if (pi->face->ifndx >= 0) {
                DEBUGMSG_CFWD(INFO, "  outgoing data=<%s>%s to=%s\n",
                          ccnl_prefix_to_path(i->pkt->pfx),
                          ccnl_suite2str(i->pkt->pfx->suite),
                          ccnl_addr2ascii(&pi->face->peer));
                DEBUGMSG_CORE(VERBOSE, "    Serve to face: %d (pkt=%p)\n",
                         pi->face->faceid, (void*) c->pkt);
                ccnl_nfn_monitor(ccnl, pi->face, c->pkt->pfx,
                                 c->pkt->content, c->pkt->contlen);
                ccnl_face_enqueue(ccnl, pi->face, buf_dup(c->pkt->buf));
            } else {// upcall to deliver content to local client
                ccnl_app_RX(ccnl, c);
            }
            c->served_cnt++;
            cnt++;
        }
        i = ccnl_interest_remove(ccnl, i);
    }
    return cnt;
}
Example #6
0
void
ccnl_interest_propagate(struct ccnl_relay_s *ccnl, struct ccnl_interest_s *i)
{
    struct ccnl_forward_s *fwd;
    int rc = 0;
#ifdef USE_NACK
    int matching_face = 0;
#endif

    if (!i)
        return;
    DEBUGMSG_CORE(DEBUG, "ccnl_interest_propagate\n");

    // CONFORM: "A node MUST implement some strategy rule, even if it is only to
    // transmit an Interest Message on all listed dest faces in sequence."
    // CCNL strategy: we forward on all FWD entries with a prefix match

    for (fwd = ccnl->fib; fwd; fwd = fwd->next) {
        if (!fwd->prefix)
            continue;

        //Only for matching suite
        if (!i->pkt->pfx || fwd->suite != i->pkt->pfx->suite) {
            DEBUGMSG_CORE(VERBOSE, "  not same suite (%d/%d)\n",
                     fwd->suite, i->pkt->pfx ? i->pkt->pfx->suite : -1);
            continue;
        }

        rc = ccnl_prefix_cmp(fwd->prefix, NULL, i->pkt->pfx, CMP_LONGEST);

        DEBUGMSG_CORE(DEBUG, "  ccnl_interest_propagate, rc=%d/%d\n",
                 rc, fwd->prefix->compcnt);
        if (rc < fwd->prefix->compcnt)
            continue;

        DEBUGMSG_CORE(DEBUG, "  ccnl_interest_propagate, fwd==%p\n", (void*)fwd);
        // suppress forwarding to origin of interest, except wireless
        if (!i->from || fwd->face != i->from ||
                                (i->from->flags & CCNL_FACE_FLAGS_REFLECT)) {
            DEBUGMSG_CFWD(INFO, "  outgoing interest=<%s> to=%s\n",
                          ccnl_prefix_to_path(i->pkt->pfx),
                          fwd->face ? ccnl_addr2ascii(&fwd->face->peer)
                                    : "<tap>");
            ccnl_nfn_monitor(ccnl, fwd->face, i->pkt->pfx, NULL, 0);

            // DEBUGMSG(DEBUG, "%p %p %p\n", (void*)i, (void*)i->pkt, (void*)i->pkt->buf);
            if (fwd->tap)
                (fwd->tap)(ccnl, i->from, i->pkt->pfx, i->pkt->buf);
            if (fwd->face)
                ccnl_face_enqueue(ccnl, fwd->face, buf_dup(i->pkt->buf));
#ifdef USE_NACK
            matching_face = 1;
#endif
        } else {
            DEBUGMSG_CORE(DEBUG, "  not forwarded\n");
        }
    }

#ifdef USE_NACK
    if(!matching_face){
        ccnl_nack_reply(ccnl, i->pkt->pfx, i->from, i->pkt->pfx->suite);
        ccnl_interest_remove(ccnl, i);
    }
#endif

    return;
}
Example #7
0
int
ccnl_ccnb_forwarder(struct ccnl_relay_s *relay, struct ccnl_face_s *from,
		    unsigned char **data, int *datalen)
{
    int rc= -1, scope=3, aok=3, minsfx=0, maxsfx=CCNL_MAX_NAME_COMP, contlen;
    struct ccnl_buf_s *buf = 0, *nonce=0, *ppkd=0;
    struct ccnl_interest_s *i = 0;
    struct ccnl_content_s *c = 0;
    struct ccnl_prefix_s *p = 0;
    unsigned char *content = 0;
    DEBUGMSG(99, "ccnl/ccnb forwarder (%d bytes left)\n", *datalen);

    buf = ccnl_ccnb_extract(data, datalen, &scope, &aok, &minsfx,
			    &maxsfx, &p, &nonce, &ppkd, &content, &contlen);
    if (!buf) {
	    DEBUGMSG(6, "  parsing error or no prefix\n"); goto Done;
    }
    if (nonce && ccnl_nonce_find_or_append(relay, nonce)) {
	DEBUGMSG(6, "  dropped because of duplicate nonce\n"); goto Skip;
    }
    if (buf->data[0] == 0x01 && buf->data[1] == 0xd2) { // interest
	DEBUGMSG(6, "  interest=<%s>\n", ccnl_prefix_to_path(p));
	ccnl_print_stats(relay, STAT_RCV_I); //log count recv_interest
	if (p->compcnt > 0 && p->comp[0][0] == (unsigned char) 0xc1) goto Skip;
	if (p->compcnt == 4 && !memcmp(p->comp[0], "ccnx", 4)) {
	    rc = ccnl_mgmt(relay, buf, p, from); goto Done;
	}
	// CONFORM: Step 1:
	if ( aok & 0x01 ) { // honor "answer-from-existing-content-store" flag
	    for (c = relay->contents; c; c = c->next) {
		if (c->suite != CCNL_SUITE_CCNB) continue;
		if (!ccnl_i_prefixof_c(p, minsfx, maxsfx, c)) continue;
		if (ppkd && !buf_equal(ppkd, c->details.ccnb.ppkd)) continue;
		// FIXME: should check stale bit in aok here
		DEBUGMSG(7, "  matching content for interest, content %p\n", (void *) c);
		ccnl_print_stats(relay, STAT_SND_C); //log sent_c
		if (from->ifndx >= 0)
		    ccnl_face_enqueue(relay, from, buf_dup(c->pkt));
		else
		    ccnl_app_RX(relay, c);
		goto Skip;
	    }
	}
	// CONFORM: Step 2: check whether interest is already known
	for (i = relay->pit; i; i = i->next) {
	    if (i->suite == CCNL_SUITE_CCNB &&
		!ccnl_prefix_cmp(i->prefix, NULL, p, CMP_EXACT) &&
		i->details.ccnb.minsuffix == minsfx &&
		i->details.ccnb.maxsuffix == maxsfx && 
		((!ppkd && !i->details.ccnb.ppkd) ||
		   buf_equal(ppkd, i->details.ccnb.ppkd)) )
		break;
	}
	if (!i) { // this is a new/unknown I request: create and propagate
	    i = ccnl_interest_new(relay, from, CCNL_SUITE_CCNB,
				  &buf, &p, minsfx, maxsfx);
	    if (ppkd)
		i->details.ccnb.ppkd = ppkd, ppkd = NULL;
	    if (i) { // CONFORM: Step 3 (and 4)
		DEBUGMSG(7, "  created new interest entry %p\n", (void *) i);
		if (scope > 2)
		    ccnl_interest_propagate(relay, i);
	    }
	} else if (scope > 2 && (from->flags & CCNL_FACE_FLAGS_FWDALLI)) {
	    DEBUGMSG(7, "  old interest, nevertheless propagated %p\n", (void *) i);
	    ccnl_interest_propagate(relay, i);
	}
	if (i) { // store the I request, for the incoming face (Step 3)
	    DEBUGMSG(7, "  appending interest entry %p\n", (void *) i);
	    ccnl_interest_append_pending(i, from);
	}
    } else { // content
	DEBUGMSG(6, "  content=<%s>\n", ccnl_prefix_to_path(p));
	ccnl_print_stats(relay, STAT_RCV_C); //log count recv_content
        
#ifdef USE_SIGNATURES
        if (p->compcnt == 2 && !memcmp(p->comp[0], "ccnx", 4)
                && !memcmp(p->comp[1], "crypto", 6) &&
                from == relay->crypto_face) {
	    rc = ccnl_crypto(relay, buf, p, from); goto Done;
	}
#endif /*USE_SIGNATURES*/
        
        // CONFORM: Step 1:
	for (c = relay->contents; c; c = c->next)
	    if (buf_equal(c->pkt, buf)) goto Skip; // content is dup
	c = ccnl_content_new(relay, CCNL_SUITE_CCNB,
			     &buf, &p, &ppkd, content, contlen);
	if (c) { // CONFORM: Step 2 (and 3)
	    if (!ccnl_content_serve_pending(relay, c)) { // unsolicited content
		// CONFORM: "A node MUST NOT forward unsolicited data [...]"
		DEBUGMSG(7, "  removed because no matching interest\n");
		free_content(c);
		goto Skip;
	    }
	    if (relay->max_cache_entries != 0) { // it's set to -1 or a limit
		DEBUGMSG(7, "  adding content to cache\n");
		ccnl_content_add2cache(relay, c);
	    } else {
		DEBUGMSG(7, "  content not added to cache\n");
		free_content(c);
	    }
	}
    }
Skip:
    rc = 0;
Done:
    free_prefix(p);
    free_3ptr_list(buf, nonce, ppkd);
    return rc;
}
Example #8
0
int ccnl_core_RX_i_or_c(struct ccnl_relay_s *relay, struct ccnl_face_s *from,
                        unsigned char **data, int *datalen)
{
    int rc = -1, scope = 3, aok = 3, minsfx = 0, maxsfx = CCNL_MAX_NAME_COMP,
        contlen;
    struct ccnl_buf_s *buf = 0, *nonce = 0, *ppkd = 0;
    struct ccnl_interest_s *i = 0;
    struct ccnl_content_s *c = 0;
    struct ccnl_prefix_s *p = 0;
    unsigned char *content = 0;
    DEBUGMSG(1, "ccnl_core_RX_i_or_c: (%d bytes left)\n", *datalen);

    buf = ccnl_extract_prefix_nonce_ppkd(data, datalen, &scope, &aok, &minsfx,
                                         &maxsfx, &p, &nonce, &ppkd, &content, &contlen);

    if (!buf) {
        DEBUGMSG(6, "  parsing error or no prefix\n");
        goto Done;
    }

    if (nonce && ccnl_nonce_find_or_append(relay, nonce)) {
        DEBUGMSG(6, "  dropped because of duplicate nonce\n");
        goto Skip;
    }

    if (buf->data[0] == 0x01 && buf->data[1] == 0xd2) { // interest
        DEBUGMSG(1, "ccnl_core_RX_i_or_c: interest=<%s>\n", ccnl_prefix_to_path(p));
        from->stat.received_interest++;

        if (p->compcnt > 0 && p->comp[0][0] == (unsigned char) 0xc1) {
            goto Skip;
        }

        if (p->compcnt == 4 && !memcmp(p->comp[0], "ccnx", 4)) {
            DEBUGMSG(1, "it's a mgnt msg!\n");
            rc = ccnl_mgmt(relay, buf, p, from);
            DEBUGMSG(1, "mgnt processing done!\n");
            goto Done;
        }

        // CONFORM: Step 1:
        if (aok & 0x01) { // honor "answer-from-existing-content-store" flag
            for (c = relay->contents; c; c = c->next) {
                if (!ccnl_i_prefixof_c(p, ppkd, minsfx, maxsfx, c)) {
                    continue;
                }

                // FIXME: should check stale bit in aok here
                DEBUGMSG(7, "  matching content for interest, content %p\n",
                         (void *) c);
                from->stat.send_content[c->served_cnt % CCNL_MAX_CONTENT_SERVED_STAT]++;
                c->served_cnt++;

                if (from->ifndx >= 0) {
                    ccnl_face_enqueue(relay, from, buf_dup(c->pkt));
                }

                goto Skip;
            }
        }

        // CONFORM: Step 2: check whether interest is already known
        for (i = relay->pit; i; i = i->next) {
            if (!ccnl_prefix_cmp(i->prefix, NULL, p, CMP_EXACT)
                && i->minsuffix == minsfx && i->maxsuffix == maxsfx
                && ((!ppkd && !i->ppkd) || buf_equal(ppkd, i->ppkd))) {
                break;
            }
        }

        if (!i) { // this is a new/unknown I request: create and propagate
            i = ccnl_interest_new(relay, from, &buf, &p, minsfx, maxsfx, &ppkd);

            if (i) { // CONFORM: Step 3 (and 4)
                DEBUGMSG(7, "  created new interest entry %p\n", (void *) i);

                if (scope > 2) {
                    ccnl_interest_propagate(relay, i);
                }
            }
        }
        else if (scope > 2 && (from->flags & CCNL_FACE_FLAGS_FWDALLI)) {
            DEBUGMSG(7, "  old interest, nevertheless propagated %p\n",
                     (void *) i);
            ccnl_interest_propagate(relay, i);
        }

        if (i) { // store the I request, for the incoming face (Step 3)
            DEBUGMSG(7, "  appending interest entry %p\n", (void *) i);
            ccnl_interest_append_pending(i, from);
        }
    }
    else {   // content
        DEBUGMSG(6, "  content=<%s>\n", ccnl_prefix_to_path(p));
        from->stat.received_content++;

        // CONFORM: Step 1:
        for (c = relay->contents; c; c = c->next) {
            if (buf_equal(c->pkt, buf)) {
                DEBUGMSG(1, "content is dup: skip\n");
                goto Skip;
            }
        }

        c = ccnl_content_new(relay, &buf, &p, &ppkd, content, contlen);

        if (c) { // CONFORM: Step 2 (and 3)
            if (!ccnl_content_serve_pending(relay, c, from)) { // unsolicited content
                // CONFORM: "A node MUST NOT forward unsolicited data [...]"
                DEBUGMSG(7, "  removed because no matching interest\n");
                free_content(c);
                goto Skip;
            }
#if CCNL_DYNAMIC_FIB
            else {
                /* content has matched an interest, we consider this name as available on this face */
                ccnl_content_learn_name_route(relay, c->name, from, relay->fib_threshold_prefix, 0);
            }
#endif

            if (relay->max_cache_entries != 0) { // it's set to -1 or a limit
                DEBUGMSG(7, "  adding content to cache\n");
                ccnl_content_add2cache(relay, c);
            }
            else {
                DEBUGMSG(7, "  content not added to cache\n");
                free_content(c);
            }
        }
    }

Skip:
    rc = 0;
Done:
    free_prefix(p);
    free_3ptr_list(buf, nonce, ppkd);
    DEBUGMSG(1, "leaving\n");
    return rc;
}