Update zero checksum support

usrsctplib/netinet/sctp_header.h

@@ -226,7 +226,7 @@ struct sctp_state_cookie {	/* this is our definition... */
 
 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
 	uint8_t loopback_scope;	/* loopback scope information */
-	uint8_t zero_checksum;	/* copy of the inp value */
+	uint8_t rcv_edmid;	/* copy of the inp value */
 	uint8_t reserved[SCTP_RESERVE_SPACE];    /* Align to 64 bits */
 	/*
 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
@@ -539,6 +539,13 @@ struct sctp_auth_chunk {
 	uint8_t hmac[];
 } SCTP_PACKED;
 
+/* Zero checksum support draft-ietf-tsvwg-sctp-zero-checksum */
+
+struct sctp_zero_checksum_acceptable {
+	struct sctp_paramhdr ph;
+	uint32_t edmid;
+} SCTP_PACKED;
+
 /*
  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
  * pieces. If ENCE is missing we could have a couple of blocks. This way we

usrsctplib/netinet/sctp_input.c

@@ -2083,7 +2083,7 @@ sctp_process_cookie_existing(struct mbuf *m, int iphlen, int offset,
 			}
 			SCTP_ZONE_FREE(SCTP_BASE_INFO(ipi_zone_asconf_ack), aack);
 		}
-		asoc->zero_checksum = cookie->zero_checksum;
+		asoc->rcv_edmid = cookie->rcv_edmid;
 
 		/* process the INIT-ACK info (my info) */
 		asoc->my_vtag = ntohl(initack_cp->init.initiate_tag);
@@ -2320,7 +2320,7 @@ sctp_process_cookie_new(struct mbuf *m, int iphlen, int offset,
 #endif
 		return (NULL);
 	}
-	asoc->zero_checksum = cookie->zero_checksum;
+	asoc->rcv_edmid = cookie->rcv_edmid;
 	/* process the INIT-ACK info (my info) */
 	asoc->my_rwnd = ntohl(initack_cp->init.a_rwnd);
 
@@ -5861,9 +5861,14 @@ sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int lengt
 			stcb = sctp_findassociation_addr(m, offset, src, dst,
 			                                 sh, ch, &inp, &net, vrf_id);
 			stcb_looked_up = true;
-			if ((stcb == NULL) || (stcb->asoc.zero_checksum == 0)) {
+			if (stcb == NULL) {
+				goto validate_cksum;
+			}
+			if (stcb->asoc.rcv_edmid == SCTP_EDMID_NONE) {
 				goto validate_cksum;
 			}
+			KASSERT(stcb->asoc.rcv_edmid == SCTP_EDMID_LOWER_LAYER_DTLS,
+				("Unexpected EDMID %u", stcb->asoc.rcv_edmid));
 			SCTP_STAT_INCR(sctps_recvzerocrc);
 		}
 	}

usrsctplib/netinet/sctp_output.c

@@ -5070,6 +5070,7 @@ sctp_send_initiate(struct sctp_inpcb *inp, struct sctp_tcb *stcb, int so_locked)
 	struct sctp_init_chunk *init;
 	struct sctp_supported_addr_param *sup_addr;
 	struct sctp_adaptation_layer_indication *ali;
+	struct sctp_zero_checksum_acceptable *zero_chksum;
 	struct sctp_supported_chunk_types_param *pr_supported;
 	struct sctp_paramhdr *ph;
 	int cnt_inits_to = 0;
@@ -5170,11 +5171,12 @@ sctp_send_initiate(struct sctp_inpcb *inp, struct sctp_tcb *stcb, int so_locked)
 	}
 
 	/* Zero checksum acceptable parameter */
-	if (stcb->asoc.zero_checksum > 0) {
-		parameter_len = (uint16_t)sizeof(struct sctp_paramhdr);
-		ph = (struct sctp_paramhdr *)(mtod(m, caddr_t) + chunk_len);
-		ph->param_type = htons(SCTP_ZERO_CHECKSUM_ACCEPTABLE);
-		ph->param_length = htons(parameter_len);
+	if (stcb->asoc.rcv_edmid != SCTP_EDMID_NONE) {
+		parameter_len = (uint16_t)sizeof(struct sctp_zero_checksum_acceptable);
+		zero_chksum = (struct sctp_zero_checksum_acceptable *)(mtod(m, caddr_t) + chunk_len);
+		zero_chksum->ph.param_type = htons(SCTP_ZERO_CHECKSUM_ACCEPTABLE);
+		zero_chksum->ph.param_length = htons(parameter_len);
+		zero_chksum->edmid = htonl(stcb->asoc.rcv_edmid);
 		chunk_len += parameter_len;
 	}
 
@@ -5493,7 +5495,7 @@ sctp_arethere_unrecognized_parameters(struct mbuf *in_initpkt,
 			break;
 		case SCTP_HAS_NAT_SUPPORT:
 			*nat_friendly = 1;
-			/* fall through */
+			/* FALLTHROUGH */
 		case SCTP_PRSCTP_SUPPORTED:
 			if (padded_size != sizeof(struct sctp_paramhdr)) {
 				SCTPDBG(SCTP_DEBUG_OUTPUT1, "Invalid size - error prsctp/nat support %d\n", plen);
@@ -5962,6 +5964,7 @@ sctp_send_initiate_ack(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 	struct mbuf *m, *m_tmp, *m_last, *m_cookie, *op_err;
 	struct sctp_init_ack_chunk *initack;
 	struct sctp_adaptation_layer_indication *ali;
+	struct sctp_zero_checksum_acceptable *zero_chksum;
 	struct sctp_supported_chunk_types_param *pr_supported;
 	struct sctp_paramhdr *ph;
 	union sctp_sockstore *over_addr;
@@ -6350,9 +6353,9 @@ sctp_send_initiate_ack(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 		}
 	}
 	if (asoc != NULL) {
-		stc.zero_checksum = asoc->zero_checksum > 0 ? 1 : 0;
+		stc.rcv_edmid = asoc->rcv_edmid;
 	} else {
-		stc.zero_checksum = inp->zero_checksum;
+		stc.rcv_edmid = inp->rcv_edmid;
 	}
 	/* Now lets put the SCTP header in place */
 	initack = mtod(m, struct sctp_init_ack_chunk *);
@@ -6477,12 +6480,17 @@ sctp_send_initiate_ack(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 	}
 
 	/* Zero checksum acceptable parameter */
-	if (((asoc != NULL) && (asoc->zero_checksum > 0)) ||
-	    ((asoc == NULL) && (inp->zero_checksum == 1))) {
-		parameter_len = (uint16_t)sizeof(struct sctp_paramhdr);
-		ph = (struct sctp_paramhdr *)(mtod(m, caddr_t) + chunk_len);
-		ph->param_type = htons(SCTP_ZERO_CHECKSUM_ACCEPTABLE);
-		ph->param_length = htons(parameter_len);
+	if (((asoc != NULL) && (asoc->rcv_edmid != SCTP_EDMID_NONE)) ||
+	    ((asoc == NULL) && (inp->rcv_edmid != SCTP_EDMID_NONE))) {
+		parameter_len = (uint16_t)sizeof(struct sctp_zero_checksum_acceptable);
+		zero_chksum = (struct sctp_zero_checksum_acceptable *)(mtod(m, caddr_t) + chunk_len);
+		zero_chksum->ph.param_type = htons(SCTP_ZERO_CHECKSUM_ACCEPTABLE);
+		zero_chksum->ph.param_length = htons(parameter_len);
+		if (asoc != NULL) {
+			zero_chksum->edmid = htonl(asoc->rcv_edmid);
+		} else {
+			zero_chksum->edmid = htonl(inp->rcv_edmid);
+		}
 		chunk_len += parameter_len;
 	}
 
@@ -9018,7 +9026,14 @@ sctp_med_chunk_output(struct sctp_inpcb *inp,
 					 * flight size since this little guy
 					 * is a control only packet.
 					 */
-					use_zero_crc = asoc->zero_checksum == 2;
+					switch (asoc->snd_edmid) {
+					case SCTP_EDMID_LOWER_LAYER_DTLS:
+						use_zero_crc = true;
+						break;
+					default:
+						use_zero_crc = false;
+						break;
+					}
 					if (asconf) {
 						sctp_timer_start(SCTP_TIMER_TYPE_ASCONF, inp, stcb, net);
 						use_zero_crc = false;
@@ -9352,8 +9367,15 @@ sctp_med_chunk_output(struct sctp_inpcb *inp,
 	no_data_fill:
 		/* Is there something to send for this destination? */
 		if (outchain) {
+			switch (asoc->snd_edmid) {
+			case SCTP_EDMID_LOWER_LAYER_DTLS:
+				use_zero_crc = true;
+				break;
+			default:
+				use_zero_crc = false;
+				break;
+			}
 			/* We may need to start a control timer or two */
-			use_zero_crc = asoc->zero_checksum == 2;
 			if (asconf) {
 				sctp_timer_start(SCTP_TIMER_TYPE_ASCONF, inp,
 						 stcb, net);
@@ -10096,7 +10118,14 @@ sctp_chunk_retransmission(struct sctp_inpcb *inp,
 	/* do we have control chunks to retransmit? */
 	if (m != NULL) {
 		/* Start a timer no matter if we succeed or fail */
-		use_zero_crc = asoc->zero_checksum == 2;
+		switch (asoc->snd_edmid) {
+		case SCTP_EDMID_LOWER_LAYER_DTLS:
+			use_zero_crc = true;
+			break;
+		default:
+			use_zero_crc = false;
+			break;
+		}
 		if (chk->rec.chunk_id.id == SCTP_COOKIE_ECHO) {
 			sctp_timer_start(SCTP_TIMER_TYPE_COOKIE, inp, stcb, chk->whoTo);
 			use_zero_crc = false;
@@ -10387,6 +10416,14 @@ sctp_chunk_retransmission(struct sctp_inpcb *inp,
 				sctp_timer_start(SCTP_TIMER_TYPE_SEND, inp, stcb, net);
 				tmr_started = 1;
 			}
+			switch (asoc->snd_edmid) {
+			case SCTP_EDMID_LOWER_LAYER_DTLS:
+				use_zero_crc = true;
+				break;
+			default:
+				use_zero_crc = false;
+				break;
+			}
 			/* Now lets send it, if there is anything to send :> */
 			if ((error = sctp_lowlevel_chunk_output(inp, stcb, net,
 			                                        (struct sockaddr *)&net->ro._l_addr, m,
@@ -10397,7 +10434,7 @@ sctp_chunk_retransmission(struct sctp_inpcb *inp,
 #if defined(__FreeBSD__) && !defined(__Userspace__)
 			                                        0, 0,
 #endif
-			                                        asoc->zero_checksum == 2,
+			                                        use_zero_crc,
 			                                        so_locked))) {
 				/* error, we could not output */
 				SCTPDBG(SCTP_DEBUG_OUTPUT3, "Gak send error %d\n", error);
@@ -11493,6 +11530,7 @@ sctp_send_abort_tcb(struct sctp_tcb *stcb, struct mbuf *operr, int so_locked)
 	uint32_t auth_offset = 0;
 	int error;
 	uint16_t cause_len, chunk_len, padding_len;
+	bool use_zero_crc;
 
 #if defined(__APPLE__) && !defined(__Userspace__)
 	if (so_locked) {
@@ -11514,6 +11552,14 @@ sctp_send_abort_tcb(struct sctp_tcb *stcb, struct mbuf *operr, int so_locked)
 	} else {
 		m_out = NULL;
 	}
+	switch (stcb->asoc.snd_edmid) {
+	case SCTP_EDMID_LOWER_LAYER_DTLS:
+		use_zero_crc = true;
+		break;
+	default:
+		use_zero_crc = false;
+		break;
+	}
 	m_abort = sctp_get_mbuf_for_msg(sizeof(struct sctp_abort_chunk), 0, M_NOWAIT, 1, MT_HEADER);
 	if (m_abort == NULL) {
 		if (m_out) {
@@ -11578,7 +11624,7 @@ sctp_send_abort_tcb(struct sctp_tcb *stcb, struct mbuf *operr, int so_locked)
 #if defined(__FreeBSD__) && !defined(__Userspace__)
 	                                        0, 0,
 #endif
-	                                        stcb->asoc.zero_checksum == 2,
+	                                        use_zero_crc,
 	                                        so_locked))) {
 		SCTPDBG(SCTP_DEBUG_OUTPUT3, "Gak send error %d\n", error);
 		if (error == ENOBUFS) {
@@ -11602,6 +11648,7 @@ sctp_send_shutdown_complete(struct sctp_tcb *stcb,
 	uint32_t vtag;
 	int error;
 	uint8_t flags;
+	bool use_zero_crc;
 
 	m_shutdown_comp = sctp_get_mbuf_for_msg(sizeof(struct sctp_chunkhdr), 0, M_NOWAIT, 1, MT_HEADER);
 	if (m_shutdown_comp == NULL) {
@@ -11615,6 +11662,14 @@ sctp_send_shutdown_complete(struct sctp_tcb *stcb,
 		flags = 0;
 		vtag = stcb->asoc.peer_vtag;
 	}
+	switch (stcb->asoc.snd_edmid) {
+	case SCTP_EDMID_LOWER_LAYER_DTLS:
+		use_zero_crc = true;
+		break;
+	default:
+		use_zero_crc = false;
+		break;
+	}
 	shutdown_complete = mtod(m_shutdown_comp, struct sctp_shutdown_complete_chunk *);
 	shutdown_complete->ch.chunk_type = SCTP_SHUTDOWN_COMPLETE;
 	shutdown_complete->ch.chunk_flags = flags;
@@ -11629,7 +11684,7 @@ sctp_send_shutdown_complete(struct sctp_tcb *stcb,
 #if defined(__FreeBSD__) && !defined(__Userspace__)
 	                                        0, 0,
 #endif
-	                                        stcb->asoc.zero_checksum == 2,
+	                                        use_zero_crc,
 	                                        SCTP_SO_NOT_LOCKED))) {
 		SCTPDBG(SCTP_DEBUG_OUTPUT3, "Gak send error %d\n", error);
 		if (error == ENOBUFS) {

usrsctplib/netinet/sctp_pcb.c

@@ -2797,7 +2797,7 @@ sctp_inpcb_alloc(struct socket *so, uint32_t vrf_id)
 	inp->nrsack_supported = (uint8_t)SCTP_BASE_SYSCTL(sctp_nrsack_enable);
 	inp->pktdrop_supported = (uint8_t)SCTP_BASE_SYSCTL(sctp_pktdrop_enable);
 	inp->idata_supported = 0;
-	inp->zero_checksum = 0;
+	inp->rcv_edmid = SCTP_EDMID_NONE;
 
 #if defined(__FreeBSD__) && !defined(__Userspace__)
 	inp->fibnum = so->so_fibnum;
@@ -7412,12 +7412,22 @@ sctp_load_addresses_from_init(struct sctp_tcb *stcb, struct mbuf *m,
 			/* Peer supports pr-sctp */
 			peer_supports_prsctp = 1;
 		} else if (ptype == SCTP_ZERO_CHECKSUM_ACCEPTABLE) {
-			/*
-			 * Only send zero checksums if the upper layer has
-			 * also enabled the support for this.
-			 */
-			if (stcb->asoc.zero_checksum == 1) {
-				stcb->asoc.zero_checksum = 2;
+			struct sctp_zero_checksum_acceptable zero_chksum, *zero_chksum_p;
+
+			phdr = sctp_get_next_param(m, offset,
+			                           (struct sctp_paramhdr *)&zero_chksum,
+			                           sizeof(struct sctp_zero_checksum_acceptable));
+			if (phdr != NULL) {
+				/*
+				 * Only send zero checksums if the upper layer
+				 * has enabled the support for the same method
+				 * as allowed by the peer.
+				 */
+				zero_chksum_p = (struct sctp_zero_checksum_acceptable *)phdr;
+				if ((ntohl(zero_chksum_p->edmid) != SCTP_EDMID_NONE) &&
+				    (ntohl(zero_chksum_p->edmid) == stcb->asoc.rcv_edmid)) {
+					stcb->asoc.snd_edmid = stcb->asoc.rcv_edmid;
+				}
 			}
 		} else if (ptype == SCTP_SUPPORTED_CHUNK_EXT) {
 			/* A supported extension chunk */

usrsctplib/netinet/sctp_pcb.h

@@ -496,7 +496,7 @@ struct sctp_inpcb {
 	uint8_t reconfig_supported;
 	uint8_t nrsack_supported;
 	uint8_t pktdrop_supported;
-	uint8_t zero_checksum;
+	uint8_t rcv_edmid;
 	struct sctp_nonpad_sndrcvinfo def_send;
 	/*-
 	 * These three are here for the sosend_dgram

usrsctplib/netinet/sctp_structs.h

@@ -1234,12 +1234,9 @@ struct sctp_association {
 	uint8_t pktdrop_supported;
 	uint8_t idata_supported;
 
-	/* Zero checksum supported information:
-	 * 0: disabled
-	 * 1: enabled for rcv
-	 * 2: enabled for snd/rcv
-	 */
-	uint8_t zero_checksum;
+	/* Zero checksum supported information */
+	uint8_t rcv_edmid;
+	uint8_t snd_edmid;
 
 	/* Did the peer make the stream config (add out) request */
 	uint8_t peer_req_out;

usrsctplib/netinet/sctp_uio.h

@@ -810,6 +810,10 @@ struct sctp_get_nonce_values {
 	uint32_t gn_local_tag;
 };
 
+/* Values for SCTP_ACCEPT_ZERO_CHECKSUM */
+#define SCTP_EDMID_NONE             0
+#define SCTP_EDMID_LOWER_LAYER_DTLS 1
+
 /* Debugging logs */
 struct sctp_str_log {
 	void *stcb; /* FIXME: LP64 issue */

usrsctplib/netinet/sctp_usrreq.c

@@ -7800,13 +7800,15 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
 		uint32_t *value;
 
 		SCTP_CHECK_AND_CAST(value, optval, uint32_t, optsize);
-		SCTP_INP_WLOCK(inp);
-		if (*value != 0) {
-			inp->zero_checksum = 1;
+		if ((*value == SCTP_EDMID_NONE) ||
+		    (*value == SCTP_EDMID_LOWER_LAYER_DTLS)) {
+			SCTP_INP_WLOCK(inp);
+			inp->rcv_edmid = *value;
+			SCTP_INP_WUNLOCK(inp);
 		} else {
-			inp->zero_checksum = 0;
+			SCTP_LTRACE_ERR_RET(inp, NULL, NULL, SCTP_FROM_SCTP_USRREQ, EINVAL);
+			error = EINVAL;
 		}
-		SCTP_INP_WUNLOCK(inp);
 		break;
 	}
 

usrsctplib/netinet/sctputil.c

@@ -1178,7 +1178,8 @@ sctp_init_asoc(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 	asoc->nrsack_supported = inp->nrsack_supported;
 	asoc->pktdrop_supported = inp->pktdrop_supported;
 	asoc->idata_supported = inp->idata_supported;
-	asoc->zero_checksum = inp->zero_checksum;
+	asoc->rcv_edmid = inp->rcv_edmid;
+	asoc->snd_edmid = SCTP_EDMID_NONE;
 	asoc->sctp_cmt_pf = (uint8_t)0;
 	asoc->sctp_frag_point = inp->sctp_frag_point;
 	asoc->sctp_features = inp->sctp_features;

usrsctplib/usrsctp.h

@@ -560,6 +560,7 @@ struct sctp_event_subscribe {
 #define SCTP_NRSACK_SUPPORTED           0x00000030
 #define SCTP_PKTDROP_SUPPORTED          0x00000031
 #define SCTP_MAX_CWND                   0x00000032
+#define SCTP_ACCEPT_ZERO_CHECKSUM       0x00000033
 
 #define SCTP_ENABLE_STREAM_RESET        0x00000900 /* struct sctp_assoc_value */
 
@@ -767,6 +768,10 @@ struct sctp_get_nonce_values {
 	uint32_t gn_local_tag;
 };
 
+/* Values for SCTP_ACCEPT_ZERO_CHECKSUM */
+#define SCTP_EDMID_NONE             0
+#define SCTP_EDMID_LOWER_LAYER_DTLS 1
+
 
 /*
  * Main SCTP chunk types