1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved. 3 * 4 * RMNET Data ingress/egress handler 5 */ 6 7 #include <linux/netdevice.h> 8 #include <linux/netdev_features.h> 9 #include <linux/if_arp.h> 10 #include <net/sock.h> 11 #include "rmnet_private.h" 12 #include "rmnet_config.h" 13 #include "rmnet_vnd.h" 14 #include "rmnet_map.h" 15 #include "rmnet_handlers.h" 16 17 #define RMNET_IP_VERSION_4 0x40 18 #define RMNET_IP_VERSION_6 0x60 19 20 /* Helper Functions */ 21 22 static void rmnet_set_skb_proto(struct sk_buff *skb) 23 { 24 switch (skb->data[0] & 0xF0) { 25 case RMNET_IP_VERSION_4: 26 skb->protocol = htons(ETH_P_IP); 27 break; 28 case RMNET_IP_VERSION_6: 29 skb->protocol = htons(ETH_P_IPV6); 30 break; 31 default: 32 skb->protocol = htons(ETH_P_MAP); 33 break; 34 } 35 } 36 37 /* Generic handler */ 38 39 static void 40 rmnet_deliver_skb(struct sk_buff *skb) 41 { 42 struct rmnet_priv *priv = netdev_priv(skb->dev); 43 44 skb_reset_transport_header(skb); 45 skb_reset_network_header(skb); 46 rmnet_vnd_rx_fixup(skb, skb->dev); 47 48 skb->pkt_type = PACKET_HOST; 49 skb_set_mac_header(skb, 0); 50 gro_cells_receive(&priv->gro_cells, skb); 51 } 52 53 /* MAP handler */ 54 55 static void 56 __rmnet_map_ingress_handler(struct sk_buff *skb, 57 struct rmnet_port *port) 58 { 59 struct rmnet_map_header *map_header = (void *)skb->data; 60 struct rmnet_endpoint *ep; 61 u16 len, pad; 62 u8 mux_id; 63 64 if (map_header->flags & MAP_CMD_FLAG) { 65 /* Packet contains a MAP command (not data) */ 66 if (port->data_format & RMNET_FLAGS_INGRESS_MAP_COMMANDS) 67 return rmnet_map_command(skb, port); 68 69 goto free_skb; 70 } 71 72 mux_id = map_header->mux_id; 73 pad = map_header->flags & MAP_PAD_LEN_MASK; 74 len = ntohs(map_header->pkt_len) - pad; 75 76 if (mux_id >= RMNET_MAX_LOGICAL_EP) 77 goto free_skb; 78 79 ep = rmnet_get_endpoint(port, mux_id); 80 if (!ep) 81 goto free_skb; 82 83 skb->dev = ep->egress_dev; 84 85 /* Subtract MAP header */ 86 skb_pull(skb, sizeof(struct rmnet_map_header)); 87 rmnet_set_skb_proto(skb); 88 89 if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) { 90 if (!rmnet_map_checksum_downlink_packet(skb, len + pad)) 91 skb->ip_summed = CHECKSUM_UNNECESSARY; 92 } 93 94 skb_trim(skb, len); 95 rmnet_deliver_skb(skb); 96 return; 97 98 free_skb: 99 kfree_skb(skb); 100 } 101 102 static void 103 rmnet_map_ingress_handler(struct sk_buff *skb, 104 struct rmnet_port *port) 105 { 106 struct sk_buff *skbn; 107 108 if (skb->dev->type == ARPHRD_ETHER) { 109 if (pskb_expand_head(skb, ETH_HLEN, 0, GFP_ATOMIC)) { 110 kfree_skb(skb); 111 return; 112 } 113 114 skb_push(skb, ETH_HLEN); 115 } 116 117 if (port->data_format & RMNET_FLAGS_INGRESS_DEAGGREGATION) { 118 while ((skbn = rmnet_map_deaggregate(skb, port)) != NULL) 119 __rmnet_map_ingress_handler(skbn, port); 120 121 consume_skb(skb); 122 } else { 123 __rmnet_map_ingress_handler(skb, port); 124 } 125 } 126 127 static int rmnet_map_egress_handler(struct sk_buff *skb, 128 struct rmnet_port *port, u8 mux_id, 129 struct net_device *orig_dev) 130 { 131 int required_headroom, additional_header_len; 132 struct rmnet_map_header *map_header; 133 134 additional_header_len = 0; 135 required_headroom = sizeof(struct rmnet_map_header); 136 137 if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) { 138 additional_header_len = sizeof(struct rmnet_map_ul_csum_header); 139 required_headroom += additional_header_len; 140 } 141 142 if (skb_headroom(skb) < required_headroom) { 143 if (pskb_expand_head(skb, required_headroom, 0, GFP_ATOMIC)) 144 return -ENOMEM; 145 } 146 147 if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) 148 rmnet_map_checksum_uplink_packet(skb, orig_dev); 149 150 map_header = rmnet_map_add_map_header(skb, additional_header_len, 0); 151 if (!map_header) 152 return -ENOMEM; 153 154 map_header->mux_id = mux_id; 155 156 skb->protocol = htons(ETH_P_MAP); 157 158 return 0; 159 } 160 161 static void 162 rmnet_bridge_handler(struct sk_buff *skb, struct net_device *bridge_dev) 163 { 164 if (skb_mac_header_was_set(skb)) 165 skb_push(skb, skb->mac_len); 166 167 if (bridge_dev) { 168 skb->dev = bridge_dev; 169 dev_queue_xmit(skb); 170 } 171 } 172 173 /* Ingress / Egress Entry Points */ 174 175 /* Processes packet as per ingress data format for receiving device. Logical 176 * endpoint is determined from packet inspection. Packet is then sent to the 177 * egress device listed in the logical endpoint configuration. 178 */ 179 rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb) 180 { 181 struct sk_buff *skb = *pskb; 182 struct rmnet_port *port; 183 struct net_device *dev; 184 185 if (!skb) 186 goto done; 187 188 if (skb_linearize(skb)) { 189 kfree_skb(skb); 190 goto done; 191 } 192 193 if (skb->pkt_type == PACKET_LOOPBACK) 194 return RX_HANDLER_PASS; 195 196 dev = skb->dev; 197 port = rmnet_get_port_rcu(dev); 198 if (unlikely(!port)) { 199 atomic_long_inc(&skb->dev->rx_nohandler); 200 kfree_skb(skb); 201 goto done; 202 } 203 204 switch (port->rmnet_mode) { 205 case RMNET_EPMODE_VND: 206 rmnet_map_ingress_handler(skb, port); 207 break; 208 case RMNET_EPMODE_BRIDGE: 209 rmnet_bridge_handler(skb, port->bridge_ep); 210 break; 211 } 212 213 done: 214 return RX_HANDLER_CONSUMED; 215 } 216 217 /* Modifies packet as per logical endpoint configuration and egress data format 218 * for egress device configured in logical endpoint. Packet is then transmitted 219 * on the egress device. 220 */ 221 void rmnet_egress_handler(struct sk_buff *skb) 222 { 223 struct net_device *orig_dev; 224 struct rmnet_port *port; 225 struct rmnet_priv *priv; 226 u8 mux_id; 227 228 sk_pacing_shift_update(skb->sk, 8); 229 230 orig_dev = skb->dev; 231 priv = netdev_priv(orig_dev); 232 skb->dev = priv->real_dev; 233 mux_id = priv->mux_id; 234 235 port = rmnet_get_port_rcu(skb->dev); 236 if (!port) 237 goto drop; 238 239 if (rmnet_map_egress_handler(skb, port, mux_id, orig_dev)) 240 goto drop; 241 242 rmnet_vnd_tx_fixup(skb, orig_dev); 243 244 dev_queue_xmit(skb); 245 return; 246 247 drop: 248 this_cpu_inc(priv->pcpu_stats->stats.tx_drops); 249 kfree_skb(skb); 250 } 251