1 /* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved. 2 * 3 * This program is free software; you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License version 2 and 5 * only version 2 as published by the Free Software Foundation. 6 * 7 * This program is distributed in the hope that it will be useful, 8 * but WITHOUT ANY WARRANTY; without even the implied warranty of 9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 * GNU General Public License for more details. 11 * 12 * RMNET Data ingress/egress handler 13 * 14 */ 15 16 #include <linux/netdevice.h> 17 #include <linux/netdev_features.h> 18 #include "rmnet_private.h" 19 #include "rmnet_config.h" 20 #include "rmnet_vnd.h" 21 #include "rmnet_map.h" 22 #include "rmnet_handlers.h" 23 24 #define RMNET_IP_VERSION_4 0x40 25 #define RMNET_IP_VERSION_6 0x60 26 27 /* Helper Functions */ 28 29 static void rmnet_set_skb_proto(struct sk_buff *skb) 30 { 31 switch (skb->data[0] & 0xF0) { 32 case RMNET_IP_VERSION_4: 33 skb->protocol = htons(ETH_P_IP); 34 break; 35 case RMNET_IP_VERSION_6: 36 skb->protocol = htons(ETH_P_IPV6); 37 break; 38 default: 39 skb->protocol = htons(ETH_P_MAP); 40 break; 41 } 42 } 43 44 /* Generic handler */ 45 46 static void 47 rmnet_deliver_skb(struct sk_buff *skb) 48 { 49 struct rmnet_priv *priv = netdev_priv(skb->dev); 50 51 skb_reset_transport_header(skb); 52 skb_reset_network_header(skb); 53 rmnet_vnd_rx_fixup(skb, skb->dev); 54 55 skb->pkt_type = PACKET_HOST; 56 skb_set_mac_header(skb, 0); 57 gro_cells_receive(&priv->gro_cells, skb); 58 } 59 60 /* MAP handler */ 61 62 static void 63 __rmnet_map_ingress_handler(struct sk_buff *skb, 64 struct rmnet_port *port) 65 { 66 struct rmnet_endpoint *ep; 67 u8 mux_id; 68 u16 len; 69 70 if (RMNET_MAP_GET_CD_BIT(skb)) { 71 if (port->ingress_data_format 72 & RMNET_INGRESS_FORMAT_MAP_COMMANDS) 73 return rmnet_map_command(skb, port); 74 75 goto free_skb; 76 } 77 78 mux_id = RMNET_MAP_GET_MUX_ID(skb); 79 len = RMNET_MAP_GET_LENGTH(skb) - RMNET_MAP_GET_PAD(skb); 80 81 if (mux_id >= RMNET_MAX_LOGICAL_EP) 82 goto free_skb; 83 84 ep = rmnet_get_endpoint(port, mux_id); 85 if (!ep) 86 goto free_skb; 87 88 skb->dev = ep->egress_dev; 89 90 /* Subtract MAP header */ 91 skb_pull(skb, sizeof(struct rmnet_map_header)); 92 skb_trim(skb, len); 93 rmnet_set_skb_proto(skb); 94 rmnet_deliver_skb(skb); 95 return; 96 97 free_skb: 98 kfree_skb(skb); 99 } 100 101 static void 102 rmnet_map_ingress_handler(struct sk_buff *skb, 103 struct rmnet_port *port) 104 { 105 struct sk_buff *skbn; 106 107 if (port->ingress_data_format & RMNET_INGRESS_FORMAT_DEAGGREGATION) { 108 while ((skbn = rmnet_map_deaggregate(skb)) != NULL) 109 __rmnet_map_ingress_handler(skbn, port); 110 111 consume_skb(skb); 112 } else { 113 __rmnet_map_ingress_handler(skb, port); 114 } 115 } 116 117 static int rmnet_map_egress_handler(struct sk_buff *skb, 118 struct rmnet_port *port, u8 mux_id, 119 struct net_device *orig_dev) 120 { 121 int required_headroom, additional_header_len; 122 struct rmnet_map_header *map_header; 123 124 additional_header_len = 0; 125 required_headroom = sizeof(struct rmnet_map_header); 126 127 if (skb_headroom(skb) < required_headroom) { 128 if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL)) 129 goto fail; 130 } 131 132 map_header = rmnet_map_add_map_header(skb, additional_header_len, 0); 133 if (!map_header) 134 goto fail; 135 136 if (port->egress_data_format & RMNET_EGRESS_FORMAT_MUXING) { 137 if (mux_id == 0xff) 138 map_header->mux_id = 0; 139 else 140 map_header->mux_id = mux_id; 141 } 142 143 skb->protocol = htons(ETH_P_MAP); 144 145 return RMNET_MAP_SUCCESS; 146 147 fail: 148 kfree_skb(skb); 149 return RMNET_MAP_CONSUMED; 150 } 151 152 static void 153 rmnet_bridge_handler(struct sk_buff *skb, struct net_device *bridge_dev) 154 { 155 if (bridge_dev) { 156 skb->dev = bridge_dev; 157 dev_queue_xmit(skb); 158 } 159 } 160 161 /* Ingress / Egress Entry Points */ 162 163 /* Processes packet as per ingress data format for receiving device. Logical 164 * endpoint is determined from packet inspection. Packet is then sent to the 165 * egress device listed in the logical endpoint configuration. 166 */ 167 rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb) 168 { 169 struct sk_buff *skb = *pskb; 170 struct rmnet_port *port; 171 struct net_device *dev; 172 173 if (!skb) 174 goto done; 175 176 dev = skb->dev; 177 port = rmnet_get_port(dev); 178 179 switch (port->rmnet_mode) { 180 case RMNET_EPMODE_VND: 181 if (port->ingress_data_format & RMNET_INGRESS_FORMAT_MAP) 182 rmnet_map_ingress_handler(skb, port); 183 break; 184 case RMNET_EPMODE_BRIDGE: 185 rmnet_bridge_handler(skb, port->bridge_ep); 186 break; 187 } 188 189 done: 190 return RX_HANDLER_CONSUMED; 191 } 192 193 /* Modifies packet as per logical endpoint configuration and egress data format 194 * for egress device configured in logical endpoint. Packet is then transmitted 195 * on the egress device. 196 */ 197 void rmnet_egress_handler(struct sk_buff *skb) 198 { 199 struct net_device *orig_dev; 200 struct rmnet_port *port; 201 struct rmnet_priv *priv; 202 u8 mux_id; 203 204 orig_dev = skb->dev; 205 priv = netdev_priv(orig_dev); 206 skb->dev = priv->real_dev; 207 mux_id = priv->mux_id; 208 209 port = rmnet_get_port(skb->dev); 210 if (!port) { 211 kfree_skb(skb); 212 return; 213 } 214 215 if (port->egress_data_format & RMNET_EGRESS_FORMAT_MAP) { 216 switch (rmnet_map_egress_handler(skb, port, mux_id, orig_dev)) { 217 case RMNET_MAP_CONSUMED: 218 return; 219 220 case RMNET_MAP_SUCCESS: 221 break; 222 223 default: 224 kfree_skb(skb); 225 return; 226 } 227 } 228 229 rmnet_vnd_tx_fixup(skb, orig_dev); 230 231 dev_queue_xmit(skb); 232 } 233