diff options
Diffstat (limited to 'drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c')
-rw-r--r-- | drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c new file mode 100644 index 000000000000..557c9bf1a469 --- /dev/null +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -0,0 +1,104 @@ +/* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * RMNET Data MAP protocol + * + */ + +#include <linux/netdevice.h> +#include "rmnet_config.h" +#include "rmnet_map.h" +#include "rmnet_private.h" + +#define RMNET_MAP_DEAGGR_SPACING 64 +#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2) + +/* Adds MAP header to front of skb->data + * Padding is calculated and set appropriately in MAP header. Mux ID is + * initialized to 0. + */ +struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb, + int hdrlen, int pad) +{ + struct rmnet_map_header *map_header; + u32 padding, map_datalen; + u8 *padbytes; + + if (skb_headroom(skb) < sizeof(struct rmnet_map_header)) + return NULL; + + map_datalen = skb->len - hdrlen; + map_header = (struct rmnet_map_header *) + skb_push(skb, sizeof(struct rmnet_map_header)); + memset(map_header, 0, sizeof(struct rmnet_map_header)); + + if (pad == RMNET_MAP_NO_PAD_BYTES) { + map_header->pkt_len = htons(map_datalen); + return map_header; + } + + padding = ALIGN(map_datalen, 4) - map_datalen; + + if (padding == 0) + goto done; + + if (skb_tailroom(skb) < padding) + return NULL; + + padbytes = (u8 *)skb_put(skb, padding); + memset(padbytes, 0, padding); + +done: + map_header->pkt_len = htons(map_datalen + padding); + map_header->pad_len = padding & 0x3F; + + return map_header; +} + +/* Deaggregates a single packet + * A whole new buffer is allocated for each portion of an aggregated frame. + * Caller should keep calling deaggregate() on the source skb until 0 is + * returned, indicating that there are no more packets to deaggregate. Caller + * is responsible for freeing the original skb. + */ +struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb) +{ + struct rmnet_map_header *maph; + struct sk_buff *skbn; + u32 packet_len; + + if (skb->len == 0) + return NULL; + + maph = (struct rmnet_map_header *)skb->data; + packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header); + + if (((int)skb->len - (int)packet_len) < 0) + return NULL; + + skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC); + if (!skbn) + return NULL; + + skbn->dev = skb->dev; + skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM); + skb_put(skbn, packet_len); + memcpy(skbn->data, skb->data, packet_len); + skb_pull(skb, packet_len); + + /* Some hardware can send us empty frames. Catch them */ + if (ntohs(maph->pkt_len) == 0) { + kfree_skb(skb); + return NULL; + } + + return skbn; +} |