1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2013-2018, 2021, 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 if ((port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) && 86 (map_header->flags & MAP_NEXT_HEADER_FLAG)) { 87 if (rmnet_map_process_next_hdr_packet(skb, len)) 88 goto free_skb; 89 skb_pull(skb, sizeof(*map_header)); 90 rmnet_set_skb_proto(skb); 91 } else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) { 92 /* Subtract MAP header */ 93 skb_pull(skb, sizeof(*map_header)); 94 rmnet_set_skb_proto(skb); 95 if (!rmnet_map_checksum_downlink_packet(skb, len + pad)) 96 skb->ip_summed = CHECKSUM_UNNECESSARY; 97 } 98 99 skb_trim(skb, len); 100 rmnet_deliver_skb(skb); 101 return; 102 103 free_skb: 104 kfree_skb(skb); 105 } 106 107 static void 108 rmnet_map_ingress_handler(struct sk_buff *skb, 109 struct rmnet_port *port) 110 { 111 struct sk_buff *skbn; 112 113 if (skb->dev->type == ARPHRD_ETHER) { 114 if (pskb_expand_head(skb, ETH_HLEN, 0, GFP_ATOMIC)) { 115 kfree_skb(skb); 116 return; 117 } 118 119 skb_push(skb, ETH_HLEN); 120 } 121 122 if (port->data_format & RMNET_FLAGS_INGRESS_DEAGGREGATION) { 123 while ((skbn = rmnet_map_deaggregate(skb, port)) != NULL) 124 __rmnet_map_ingress_handler(skbn, port); 125 126 consume_skb(skb); 127 } else { 128 __rmnet_map_ingress_handler(skb, port); 129 } 130 } 131 132 static int rmnet_map_egress_handler(struct sk_buff *skb, 133 struct rmnet_port *port, u8 mux_id, 134 struct net_device *orig_dev) 135 { 136 int required_headroom, additional_header_len, csum_type = 0; 137 struct rmnet_map_header *map_header; 138 139 additional_header_len = 0; 140 required_headroom = sizeof(struct rmnet_map_header); 141 142 if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) { 143 additional_header_len = sizeof(struct rmnet_map_ul_csum_header); 144 csum_type = RMNET_FLAGS_EGRESS_MAP_CKSUMV4; 145 } else if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5) { 146 additional_header_len = sizeof(struct rmnet_map_v5_csum_header); 147 csum_type = RMNET_FLAGS_EGRESS_MAP_CKSUMV5; 148 } 149 150 required_headroom += additional_header_len; 151 152 if (skb_cow_head(skb, required_headroom) < 0) 153 return -ENOMEM; 154 155 if (csum_type) 156 rmnet_map_checksum_uplink_packet(skb, port, orig_dev, 157 csum_type); 158 159 map_header = rmnet_map_add_map_header(skb, additional_header_len, 160 port, 0); 161 if (!map_header) 162 return -ENOMEM; 163 164 map_header->mux_id = mux_id; 165 166 skb->protocol = htons(ETH_P_MAP); 167 168 return 0; 169 } 170 171 static void 172 rmnet_bridge_handler(struct sk_buff *skb, struct net_device *bridge_dev) 173 { 174 if (skb_mac_header_was_set(skb)) 175 skb_push(skb, skb->mac_len); 176 177 if (bridge_dev) { 178 skb->dev = bridge_dev; 179 dev_queue_xmit(skb); 180 } 181 } 182 183 /* Ingress / Egress Entry Points */ 184 185 /* Processes packet as per ingress data format for receiving device. Logical 186 * endpoint is determined from packet inspection. Packet is then sent to the 187 * egress device listed in the logical endpoint configuration. 188 */ 189 rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb) 190 { 191 struct sk_buff *skb = *pskb; 192 struct rmnet_port *port; 193 struct net_device *dev; 194 195 if (!skb) 196 goto done; 197 198 if (skb_linearize(skb)) { 199 kfree_skb(skb); 200 goto done; 201 } 202 203 if (skb->pkt_type == PACKET_LOOPBACK) 204 return RX_HANDLER_PASS; 205 206 dev = skb->dev; 207 port = rmnet_get_port_rcu(dev); 208 if (unlikely(!port)) { 209 atomic_long_inc(&skb->dev->rx_nohandler); 210 kfree_skb(skb); 211 goto done; 212 } 213 214 switch (port->rmnet_mode) { 215 case RMNET_EPMODE_VND: 216 rmnet_map_ingress_handler(skb, port); 217 break; 218 case RMNET_EPMODE_BRIDGE: 219 rmnet_bridge_handler(skb, port->bridge_ep); 220 break; 221 } 222 223 done: 224 return RX_HANDLER_CONSUMED; 225 } 226 227 /* Modifies packet as per logical endpoint configuration and egress data format 228 * for egress device configured in logical endpoint. Packet is then transmitted 229 * on the egress device. 230 */ 231 void rmnet_egress_handler(struct sk_buff *skb) 232 { 233 struct net_device *orig_dev; 234 struct rmnet_port *port; 235 struct rmnet_priv *priv; 236 u8 mux_id; 237 238 sk_pacing_shift_update(skb->sk, 8); 239 240 orig_dev = skb->dev; 241 priv = netdev_priv(orig_dev); 242 skb->dev = priv->real_dev; 243 mux_id = priv->mux_id; 244 245 port = rmnet_get_port_rcu(skb->dev); 246 if (!port) 247 goto drop; 248 249 if (rmnet_map_egress_handler(skb, port, mux_id, orig_dev)) 250 goto drop; 251 252 rmnet_vnd_tx_fixup(skb, orig_dev); 253 254 dev_queue_xmit(skb); 255 return; 256 257 drop: 258 this_cpu_inc(priv->pcpu_stats->stats.tx_drops); 259 kfree_skb(skb); 260 } 261