431 lines
11 KiB
C
431 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
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*
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* RMNET Data MAP protocol
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*/
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#include <linux/netdevice.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <net/ip6_checksum.h>
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#include "rmnet_config.h"
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#include "rmnet_map.h"
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#include "rmnet_private.h"
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#define RMNET_MAP_DEAGGR_SPACING 64
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#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
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static __sum16 *rmnet_map_get_csum_field(unsigned char protocol,
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const void *txporthdr)
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{
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__sum16 *check = NULL;
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switch (protocol) {
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case IPPROTO_TCP:
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check = &(((struct tcphdr *)txporthdr)->check);
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break;
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case IPPROTO_UDP:
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check = &(((struct udphdr *)txporthdr)->check);
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break;
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default:
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check = NULL;
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break;
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}
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return check;
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}
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static int
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rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
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struct rmnet_map_dl_csum_trailer *csum_trailer,
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struct rmnet_priv *priv)
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{
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__sum16 *csum_field, csum_temp, pseudo_csum, hdr_csum, ip_payload_csum;
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u16 csum_value, csum_value_final;
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struct iphdr *ip4h;
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void *txporthdr;
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__be16 addend;
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ip4h = (struct iphdr *)(skb->data);
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if ((ntohs(ip4h->frag_off) & IP_MF) ||
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((ntohs(ip4h->frag_off) & IP_OFFSET) > 0)) {
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priv->stats.csum_fragmented_pkt++;
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return -EOPNOTSUPP;
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}
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txporthdr = skb->data + ip4h->ihl * 4;
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csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
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if (!csum_field) {
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priv->stats.csum_err_invalid_transport++;
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return -EPROTONOSUPPORT;
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}
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/* RFC 768 - Skip IPv4 UDP packets where sender checksum field is 0 */
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if (*csum_field == 0 && ip4h->protocol == IPPROTO_UDP) {
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priv->stats.csum_skipped++;
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return 0;
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}
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csum_value = ~ntohs(csum_trailer->csum_value);
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hdr_csum = ~ip_fast_csum(ip4h, (int)ip4h->ihl);
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ip_payload_csum = csum16_sub((__force __sum16)csum_value,
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(__force __be16)hdr_csum);
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pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
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ntohs(ip4h->tot_len) - ip4h->ihl * 4,
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ip4h->protocol, 0);
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addend = (__force __be16)ntohs((__force __be16)pseudo_csum);
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pseudo_csum = csum16_add(ip_payload_csum, addend);
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addend = (__force __be16)ntohs((__force __be16)*csum_field);
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csum_temp = ~csum16_sub(pseudo_csum, addend);
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csum_value_final = (__force u16)csum_temp;
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if (unlikely(csum_value_final == 0)) {
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switch (ip4h->protocol) {
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case IPPROTO_UDP:
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/* RFC 768 - DL4 1's complement rule for UDP csum 0 */
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csum_value_final = ~csum_value_final;
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break;
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case IPPROTO_TCP:
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/* DL4 Non-RFC compliant TCP checksum found */
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if (*csum_field == (__force __sum16)0xFFFF)
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csum_value_final = ~csum_value_final;
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break;
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}
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}
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if (csum_value_final == ntohs((__force __be16)*csum_field)) {
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priv->stats.csum_ok++;
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return 0;
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} else {
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priv->stats.csum_validation_failed++;
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return -EINVAL;
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}
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}
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#if IS_ENABLED(CONFIG_IPV6)
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static int
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rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
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struct rmnet_map_dl_csum_trailer *csum_trailer,
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struct rmnet_priv *priv)
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{
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__sum16 *csum_field, ip6_payload_csum, pseudo_csum, csum_temp;
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u16 csum_value, csum_value_final;
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__be16 ip6_hdr_csum, addend;
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struct ipv6hdr *ip6h;
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void *txporthdr;
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u32 length;
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ip6h = (struct ipv6hdr *)(skb->data);
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txporthdr = skb->data + sizeof(struct ipv6hdr);
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csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
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if (!csum_field) {
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priv->stats.csum_err_invalid_transport++;
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return -EPROTONOSUPPORT;
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}
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csum_value = ~ntohs(csum_trailer->csum_value);
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ip6_hdr_csum = (__force __be16)
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~ntohs((__force __be16)ip_compute_csum(ip6h,
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(int)(txporthdr - (void *)(skb->data))));
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ip6_payload_csum = csum16_sub((__force __sum16)csum_value,
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ip6_hdr_csum);
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length = (ip6h->nexthdr == IPPROTO_UDP) ?
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ntohs(((struct udphdr *)txporthdr)->len) :
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ntohs(ip6h->payload_len);
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pseudo_csum = ~(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
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length, ip6h->nexthdr, 0));
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addend = (__force __be16)ntohs((__force __be16)pseudo_csum);
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pseudo_csum = csum16_add(ip6_payload_csum, addend);
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addend = (__force __be16)ntohs((__force __be16)*csum_field);
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csum_temp = ~csum16_sub(pseudo_csum, addend);
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csum_value_final = (__force u16)csum_temp;
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if (unlikely(csum_value_final == 0)) {
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switch (ip6h->nexthdr) {
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case IPPROTO_UDP:
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/* RFC 2460 section 8.1
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* DL6 One's complement rule for UDP checksum 0
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*/
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csum_value_final = ~csum_value_final;
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break;
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case IPPROTO_TCP:
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/* DL6 Non-RFC compliant TCP checksum found */
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if (*csum_field == (__force __sum16)0xFFFF)
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csum_value_final = ~csum_value_final;
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break;
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}
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}
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if (csum_value_final == ntohs((__force __be16)*csum_field)) {
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priv->stats.csum_ok++;
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return 0;
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} else {
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priv->stats.csum_validation_failed++;
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return -EINVAL;
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}
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}
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#endif
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static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr)
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{
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struct iphdr *ip4h = (struct iphdr *)iphdr;
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void *txphdr;
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u16 *csum;
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txphdr = iphdr + ip4h->ihl * 4;
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if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
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csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
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*csum = ~(*csum);
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}
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}
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static void
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rmnet_map_ipv4_ul_csum_header(void *iphdr,
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struct rmnet_map_ul_csum_header *ul_header,
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struct sk_buff *skb)
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{
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struct iphdr *ip4h = (struct iphdr *)iphdr;
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__be16 *hdr = (__be16 *)ul_header, offset;
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offset = htons((__force u16)(skb_transport_header(skb) -
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(unsigned char *)iphdr));
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ul_header->csum_start_offset = offset;
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ul_header->csum_insert_offset = skb->csum_offset;
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ul_header->csum_enabled = 1;
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if (ip4h->protocol == IPPROTO_UDP)
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ul_header->udp_ind = 1;
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else
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ul_header->udp_ind = 0;
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/* Changing remaining fields to network order */
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hdr++;
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*hdr = htons((__force u16)*hdr);
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skb->ip_summed = CHECKSUM_NONE;
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rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);
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}
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#if IS_ENABLED(CONFIG_IPV6)
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static void rmnet_map_complement_ipv6_txporthdr_csum_field(void *ip6hdr)
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{
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struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr;
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void *txphdr;
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u16 *csum;
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txphdr = ip6hdr + sizeof(struct ipv6hdr);
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if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {
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csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);
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*csum = ~(*csum);
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}
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}
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static void
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rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
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struct rmnet_map_ul_csum_header *ul_header,
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struct sk_buff *skb)
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{
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struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr;
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__be16 *hdr = (__be16 *)ul_header, offset;
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offset = htons((__force u16)(skb_transport_header(skb) -
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(unsigned char *)ip6hdr));
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ul_header->csum_start_offset = offset;
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ul_header->csum_insert_offset = skb->csum_offset;
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ul_header->csum_enabled = 1;
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if (ip6h->nexthdr == IPPROTO_UDP)
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ul_header->udp_ind = 1;
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else
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ul_header->udp_ind = 0;
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/* Changing remaining fields to network order */
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hdr++;
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*hdr = htons((__force u16)*hdr);
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skb->ip_summed = CHECKSUM_NONE;
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rmnet_map_complement_ipv6_txporthdr_csum_field(ip6hdr);
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}
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#endif
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/* Adds MAP header to front of skb->data
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* Padding is calculated and set appropriately in MAP header. Mux ID is
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* initialized to 0.
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*/
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struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
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int hdrlen, int pad)
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{
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struct rmnet_map_header *map_header;
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u32 padding, map_datalen;
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u8 *padbytes;
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map_datalen = skb->len - hdrlen;
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map_header = (struct rmnet_map_header *)
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skb_push(skb, sizeof(struct rmnet_map_header));
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memset(map_header, 0, sizeof(struct rmnet_map_header));
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if (pad == RMNET_MAP_NO_PAD_BYTES) {
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map_header->pkt_len = htons(map_datalen);
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return map_header;
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}
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padding = ALIGN(map_datalen, 4) - map_datalen;
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if (padding == 0)
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goto done;
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if (skb_tailroom(skb) < padding)
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return NULL;
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padbytes = (u8 *)skb_put(skb, padding);
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memset(padbytes, 0, padding);
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done:
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map_header->pkt_len = htons(map_datalen + padding);
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map_header->pad_len = padding & 0x3F;
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return map_header;
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}
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/* Deaggregates a single packet
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* A whole new buffer is allocated for each portion of an aggregated frame.
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* Caller should keep calling deaggregate() on the source skb until 0 is
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* returned, indicating that there are no more packets to deaggregate. Caller
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* is responsible for freeing the original skb.
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*/
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struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
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struct rmnet_port *port)
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{
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struct rmnet_map_header *maph;
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struct sk_buff *skbn;
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u32 packet_len;
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if (skb->len == 0)
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return NULL;
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maph = (struct rmnet_map_header *)skb->data;
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packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header);
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if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
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packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
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if (((int)skb->len - (int)packet_len) < 0)
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return NULL;
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/* Some hardware can send us empty frames. Catch them */
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if (ntohs(maph->pkt_len) == 0)
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return NULL;
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skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
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if (!skbn)
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return NULL;
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skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
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skb_put(skbn, packet_len);
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memcpy(skbn->data, skb->data, packet_len);
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skb_pull(skb, packet_len);
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return skbn;
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}
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/* Validates packet checksums. Function takes a pointer to
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* the beginning of a buffer which contains the IP payload +
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* padding + checksum trailer.
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* Only IPv4 and IPv6 are supported along with TCP & UDP.
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* Fragmented or tunneled packets are not supported.
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*/
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int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len)
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{
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struct rmnet_priv *priv = netdev_priv(skb->dev);
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struct rmnet_map_dl_csum_trailer *csum_trailer;
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if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
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priv->stats.csum_sw++;
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return -EOPNOTSUPP;
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}
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csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len);
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if (!csum_trailer->valid) {
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priv->stats.csum_valid_unset++;
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return -EINVAL;
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}
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if (skb->protocol == htons(ETH_P_IP)) {
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return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv);
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} else if (skb->protocol == htons(ETH_P_IPV6)) {
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#if IS_ENABLED(CONFIG_IPV6)
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return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv);
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#else
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priv->stats.csum_err_invalid_ip_version++;
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return -EPROTONOSUPPORT;
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#endif
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} else {
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priv->stats.csum_err_invalid_ip_version++;
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return -EPROTONOSUPPORT;
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}
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return 0;
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}
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/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP
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* packets that are supported for UL checksum offload.
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*/
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void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
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struct net_device *orig_dev)
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{
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struct rmnet_priv *priv = netdev_priv(orig_dev);
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struct rmnet_map_ul_csum_header *ul_header;
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void *iphdr;
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ul_header = (struct rmnet_map_ul_csum_header *)
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skb_push(skb, sizeof(struct rmnet_map_ul_csum_header));
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if (unlikely(!(orig_dev->features &
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(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))))
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goto sw_csum;
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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iphdr = (char *)ul_header +
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sizeof(struct rmnet_map_ul_csum_header);
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if (skb->protocol == htons(ETH_P_IP)) {
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rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);
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return;
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} else if (skb->protocol == htons(ETH_P_IPV6)) {
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#if IS_ENABLED(CONFIG_IPV6)
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rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
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return;
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#else
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priv->stats.csum_err_invalid_ip_version++;
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goto sw_csum;
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#endif
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} else {
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priv->stats.csum_err_invalid_ip_version++;
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}
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}
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sw_csum:
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ul_header->csum_start_offset = 0;
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ul_header->csum_insert_offset = 0;
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ul_header->csum_enabled = 0;
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ul_header->udp_ind = 0;
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priv->stats.csum_sw++;
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}
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