net/ethernet: Let's remove the use for ll reserve

There is no need to reserve any space for each frag, as the l2 will
allocate a frag for the ethernet header, arp will do the same.

This is one step further to removing the concept of ll reserve.

Signed-off-by: Tomasz Bursztyka <[email protected]>

Author: Tomasz Bursztyka

drivers/ethernet/eth_dw.c

@@ -172,21 +172,13 @@ static void eth_tx_data(struct eth_runtime *context, u8_t *data, u16_t len)
 static int eth_tx(struct device *dev, struct net_pkt *pkt)
 {
 	struct eth_runtime *context = dev->driver_data;
+	struct net_buf *frag;
 
 	/* Ensure we're clear to transmit. */
 	eth_tx_spin_wait(context);
 
-	if (!pkt->frags) {
-		eth_tx_data(context, net_pkt_ll(pkt),
-			    net_pkt_ll_reserve(pkt));
-	} else {
-		struct net_buf *frag;
-
-		eth_tx_data(context, net_pkt_ll(pkt),
-			    net_pkt_ll_reserve(pkt) + pkt->frags->len);
-		for (frag = pkt->frags->frags; frag; frag = frag->frags) {
-			eth_tx_data(context, frag->data, frag->len);
-		}
+	for (frag = pkt->frags; frag; frag = frag->frags) {
+		eth_tx_data(context, frag->data, frag->len);
 	}
 
 	return 0;

drivers/ethernet/eth_e1000.c

@@ -52,13 +52,10 @@ static enum ethernet_hw_caps e1000_caps(struct device *dev)
 
 static size_t e1000_linearize(struct net_pkt *pkt, void *buf, size_t bufsize)
 {
-	size_t len = net_pkt_ll_reserve(pkt) + pkt->frags->len;
+	size_t len = 0;
 	struct net_buf *nb;
 
-	/* First fragment contains link layer (Ethernet) header */
-	memcpy(buf, net_pkt_ll(pkt), len);
-
-	for (nb = pkt->frags->frags; nb; nb = nb->frags) {
+	for (nb = pkt->frags; nb; nb = nb->frags) {
 		memcpy((u8_t *) buf + len, nb->data, nb->len);
 		len += nb->len;
 	}

drivers/ethernet/eth_enc28j60.c

@@ -409,9 +409,8 @@ static void eth_enc28j60_init_phy(struct device *dev)
 static int eth_enc28j60_tx(struct device *dev, struct net_pkt *pkt)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
-	u16_t len = net_pkt_ll_reserve(pkt) + net_pkt_get_len(pkt);
 	u16_t tx_bufaddr = ENC28J60_TXSTART;
-	bool first_frag = true;
+	u16_t len = net_pkt_get_len(pkt);
 	u8_t per_packet_control;
 	u16_t tx_bufaddr_end;
 	struct net_buf *frag;
@@ -446,19 +445,7 @@ static int eth_enc28j60_tx(struct device *dev, struct net_pkt *pkt)
 	eth_enc28j60_write_mem(dev, &per_packet_control, 1);
 
 	for (frag = pkt->frags; frag; frag = frag->frags) {
-		u8_t *data_ptr;
-		u16_t data_len;
-
-		if (first_frag) {
-			data_ptr = net_pkt_ll(pkt);
-			data_len = net_pkt_ll_reserve(pkt) + frag->len;
-			first_frag = false;
-		} else {
-			data_ptr = frag->data;
-			data_len = frag->len;
-		}
-
-		eth_enc28j60_write_mem(dev, data_ptr, data_len);
+		eth_enc28j60_write_mem(dev, frag->data, frag->len);
 	}
 
 	tx_bufaddr_end = tx_bufaddr + len;

drivers/ethernet/eth_mcux.c

@@ -470,7 +470,7 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 	bool timestamped_frame;
 #endif
 
-	u16_t total_len = net_pkt_ll_reserve(pkt) + net_pkt_get_len(pkt);
+	u16_t total_len = net_pkt_get_len(pkt);
 
 	k_sem_take(&context->tx_buf_sem, K_FOREVER);
 
@@ -479,18 +479,9 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 	 */
 	imask = irq_lock();
 
-	/* Gather fragment buffers into flat Ethernet frame buffer
-	 * which can be fed to MCUX Ethernet functions. First
-	 * fragment is special - it contains link layer (Ethernet
-	 * in our case) headers and must be treated specially.
-	 */
+	/* Copy the fragments */
 	dst = context->frame_buf;
-	memcpy(dst, net_pkt_ll(pkt),
-	       net_pkt_ll_reserve(pkt) + pkt->frags->len);
-	dst += net_pkt_ll_reserve(pkt) + pkt->frags->len;
-
-	/* Continue with the rest of fragments (which contain only data) */
-	frag = pkt->frags->frags;
+	frag = pkt->frags;
 	while (frag) {
 		memcpy(dst, frag->data, frag->len);
 		dst += frag->len;

drivers/ethernet/eth_native_posix.c

@@ -120,16 +120,10 @@ static struct gptp_hdr *check_gptp_msg(struct net_if *iface,
 				       struct net_pkt *pkt,
 				       bool is_tx)
 {
+	u8_t *msg_start = net_pkt_ll(pkt);
 	struct gptp_hdr *gptp_hdr;
-	u8_t *msg_start;
 	int eth_hlen;
 
-	if (net_pkt_ll_reserve(pkt)) {
-		msg_start = net_pkt_ll(pkt);
-	} else {
-		msg_start = net_pkt_ip_data(pkt);
-	}
-
 #if defined(CONFIG_NET_VLAN)
 	if (net_eth_get_vlan_status(iface)) {
 		struct net_eth_vlan_hdr *hdr_vlan;
@@ -220,13 +214,7 @@ static int eth_send(struct device *dev, struct net_pkt *pkt)
 	int count = 0;
 	int ret;
 
-	/* First fragment contains link layer (Ethernet) headers.
-	 */
-	count = net_pkt_ll_reserve(pkt) + pkt->frags->len;
-	memcpy(ctx->send, net_pkt_ll(pkt), count);
-
-	/* Then the remaining data */
-	frag = pkt->frags->frags;
+	frag = pkt->frags;
 	while (frag) {
 		memcpy(ctx->send + count, frag->data, frag->len);
 		count += frag->len;

drivers/ethernet/eth_sam_gmac.c

@@ -330,17 +330,12 @@ static struct gptp_hdr *check_gptp_msg(struct net_if *iface,
 				       struct net_pkt *pkt,
 				       bool is_tx)
 {
+	u8_t *msg_start = net_pkt_ll(pkt);
 	struct ethernet_context *eth_ctx;
 	struct gptp_hdr *gptp_hdr;
 	int eth_hlen;
 	u8_t *msg_start;
 
-	if (net_pkt_ll_reserve(pkt)) {
-		msg_start = net_pkt_ll(pkt);
-	} else {
-		msg_start = net_pkt_ip_data(pkt);
-	}
-
 #if defined(CONFIG_NET_VLAN)
 	eth_ctx = net_if_l2_data(iface);
 	if (net_eth_is_vlan_enabled(eth_ctx, iface)) {
@@ -1318,7 +1313,7 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 	struct gmac_desc_list *tx_desc_list;
 	struct gmac_desc *tx_desc;
 	struct net_buf *frag;
-	u8_t *frag_data, *frag_orig;
+	u8_t *frag_data;
 	u16_t frag_len;
 	u32_t err_tx_flushed_count_at_entry;
 	unsigned int key;
@@ -1343,15 +1338,6 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 	tx_desc_list = &queue->tx_desc_list;
 	err_tx_flushed_count_at_entry = queue->err_tx_flushed_count;
 
-	/* Store the original frag data pointer */
-	frag_orig = pkt->frags->data;
-
-	/* First fragment is special - it contains link layer (Ethernet
-	 * in our case) header. Modify the data pointer to account for more data
-	 * in the beginning of the buffer.
-	 */
-	net_buf_push(pkt->frags, net_pkt_ll_reserve(pkt));
-
 	frag = pkt->frags;
 	while (frag) {
 		frag_data = frag->data;
@@ -1403,9 +1389,6 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 		frag = frag->frags;
 	}
 
-	/* Restore the original frag data pointer */
-	pkt->frags->data = frag_orig;
-
 	key = irq_lock();
 
 	/* Check if tx_error_handler() function was executed */

drivers/ethernet/eth_stellaris.c

@@ -73,13 +73,6 @@ static int eth_stellaris_send(struct device *dev, struct net_pkt *pkt)
 	eth_stellaris_send_byte(dev, data_len & 0xff);
 	eth_stellaris_send_byte(dev, (data_len & 0xff00) >> 8);
 
-	/* Send the header, header is 14 bytes */
-	head_len_left = net_pkt_ll_reserve(pkt);
-	eth_hdr = net_pkt_ll(pkt);
-	for (i = 0; i < head_len_left; ++i) {
-		eth_stellaris_send_byte(dev, eth_hdr[i]);
-	}
-
 	/* Send the payload */
 	for (frag = pkt->frags; frag; frag = frag->frags) {
 		for (i = 0; i < frag->len; ++i) {

drivers/ethernet/eth_stm32_hal.c

@@ -74,7 +74,7 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 
 	k_mutex_lock(&dev_data->tx_mutex, K_FOREVER);
 
-	total_len = net_pkt_ll_reserve(pkt) + net_pkt_get_len(pkt);
+	total_len = net_pkt_get_len(pkt);
 	if (total_len > ETH_TX_BUF_SIZE) {
 		LOG_ERR("PKT to big");
 		res = -EIO;
@@ -88,11 +88,7 @@ static int eth_tx(struct device *dev, struct net_pkt *pkt)
 
 	dma_buffer = (u8_t *)(dma_tx_desc->Buffer1Addr);
 
-	memcpy(dma_buffer, net_pkt_ll(pkt),
-		net_pkt_ll_reserve(pkt) + pkt->frags->len);
-	dma_buffer += net_pkt_ll_reserve(pkt) + pkt->frags->len;
-
-	frag = pkt->frags->frags;
+	frag = pkt->frags;
 	while (frag) {
 		memcpy(dma_buffer, frag->data, frag->len);
 		dma_buffer += frag->len;

drivers/net/slip.c

@@ -138,10 +138,6 @@ static void slip_writeb_esc(unsigned char c)
 static int slip_send(struct device *dev, struct net_pkt *pkt)
 {
 	struct net_buf *frag;
-#if defined(CONFIG_SLIP_TAP)
-	u16_t ll_reserve = net_pkt_ll_reserve(pkt);
-	bool send_header_once = false;
-#endif
 	u8_t *ptr;
 	u16_t i;
 	u8_t c;
@@ -156,52 +152,18 @@ static int slip_send(struct device *dev, struct net_pkt *pkt)
 	slip_writeb(SLIP_END);
 
 	for (frag = pkt->frags; frag; frag = frag->frags) {
-#if defined(CONFIG_SLIP_TAP)
-		ptr = frag->data - ll_reserve;
-
-		/* This writes ethernet header */
-		if (!send_header_once && ll_reserve) {
-			for (i = 0U; i < ll_reserve; i++) {
-				slip_writeb_esc(*ptr++);
-			}
-		}
-
-		if (net_if_get_mtu(net_pkt_iface(pkt)) >
-		    net_buf_headroom(frag)) {
-			/* Do not add link layer header if the mtu is bigger
-			 * than fragment size. The first packet needs the
-			 * link layer header always.
-			 */
-			send_header_once = true;
-			ll_reserve = 0U;
-			ptr = frag->data;
-		}
-#else
-		/* There is no ll header in tun device */
 		ptr = frag->data;
-#endif
-
 		for (i = 0U; i < frag->len; ++i) {
 			c = *ptr++;
 			slip_writeb_esc(c);
 		}
 
 		if (LOG_LEVEL >= LOG_LEVEL_DBG) {
-			int frag_count = 0;
-
-			LOG_DBG("sent data %d bytes",
-				frag->len + net_pkt_ll_reserve(pkt));
-
-			if (frag->len + net_pkt_ll_reserve(pkt)) {
-				char msg[8 + 1];
-
-				snprintf(msg, sizeof(msg), "<slip %2d",
-					 frag_count++);
+			LOG_DBG("sent data %d bytes", frag->len);
 
+			if (frag->len) {
 				LOG_HEXDUMP_DBG(net_pkt_ll(pkt),
-						frag->len +
-						net_pkt_ll_reserve(pkt),
-						msg);
+						frag->len, "<slip ");
 			}
 		}
 	}

subsys/net/l2/ethernet/arp.c

@@ -234,17 +234,10 @@ static inline struct net_pkt *arp_prepare(struct net_if *iface,
 					  struct net_pkt *pending,
 					  struct in_addr *current_ip)
 {
-	struct ethernet_context *ctx = net_if_l2_data(iface);
-	int eth_hdr_len = sizeof(struct net_eth_hdr);
 	struct net_pkt *pkt;
 	struct net_arp_hdr *hdr;
 	struct in_addr *my_addr;
 
-	if (net_eth_is_vlan_enabled(ctx, iface) &&
-	    net_eth_get_vlan_tag(iface) != NET_VLAN_TAG_UNSPEC) {
-		eth_hdr_len = sizeof(struct net_eth_vlan_hdr);
-	}
-
 	if (current_ip) {
 		/* This is the IPv4 autoconf case where we have already
 		 * things setup so no need to allocate new net_pkt
@@ -253,7 +246,7 @@ static inline struct net_pkt *arp_prepare(struct net_if *iface,
 	} else {
 		struct net_buf *frag;
 
-		pkt = net_pkt_get_reserve_tx(eth_hdr_len, NET_BUF_TIMEOUT);
+		pkt = net_pkt_get_reserve_tx(0, NET_BUF_TIMEOUT);
 		if (!pkt) {
 			return NULL;
 		}
@@ -332,16 +325,13 @@ struct net_pkt *net_arp_prepare(struct net_pkt *pkt,
 				struct in_addr *request_ip,
 				struct in_addr *current_ip)
 {
-	struct ethernet_context *ctx;
 	struct arp_entry *entry;
 	struct in_addr *addr;
 
 	if (!pkt || !pkt->frags) {
 		return NULL;
 	}
 
-	ctx = net_if_l2_data(net_pkt_iface(pkt));
-
 	/* Is the destination in the local network, if not route via
 	 * the gateway address.
 	 */
@@ -476,19 +466,12 @@ static void arp_update(struct net_if *iface,
 static inline struct net_pkt *arp_prepare_reply(struct net_if *iface,
 						struct net_pkt *req)
 {
-	struct ethernet_context *ctx = net_if_l2_data(iface);
-	int eth_hdr_len = sizeof(struct net_eth_hdr);
 	struct net_pkt *pkt;
 	struct net_buf *frag;
 	struct net_arp_hdr *hdr, *query;
 	struct net_eth_hdr *eth_query;
 
-	if (net_eth_is_vlan_enabled(ctx, iface) &&
-	    net_eth_get_vlan_tag(iface) != NET_VLAN_TAG_UNSPEC) {
-		eth_hdr_len = sizeof(struct net_eth_vlan_hdr);
-	}
-
-	pkt = net_pkt_get_reserve_tx(eth_hdr_len, NET_BUF_TIMEOUT);
+	pkt = net_pkt_get_reserve_tx(0, NET_BUF_TIMEOUT);
 	if (!pkt) {
 		goto fail;
 	}
@@ -561,11 +544,13 @@ enum net_verdict net_arp_input(struct net_pkt *pkt)
 	struct in_addr *addr;
 
 	if (net_pkt_get_len(pkt) < (sizeof(struct net_arp_hdr) -
-				    net_pkt_ll_reserve(pkt))) {
+				    (net_pkt_ip_data(pkt) -
+				     net_pkt_ll(pkt)))) {
 		NET_DBG("Invalid ARP header (len %zu, min %zu bytes)",
 			net_pkt_get_len(pkt),
 			sizeof(struct net_arp_hdr) -
-			net_pkt_ll_reserve(pkt));
+			(net_pkt_ip_data(pkt) -
+			 net_pkt_ll(pkt)));
 		return NET_DROP;
 	}