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 | 520 |
1 files changed, 520 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 000000000..ba194698c --- /dev/null +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -0,0 +1,520 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved. + * + * RMNET Data MAP protocol + */ + +#include <linux/netdevice.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <net/ip6_checksum.h> +#include <linux/bitfield.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) + +static __sum16 *rmnet_map_get_csum_field(unsigned char protocol, + const void *txporthdr) +{ + if (protocol == IPPROTO_TCP) + return &((struct tcphdr *)txporthdr)->check; + + if (protocol == IPPROTO_UDP) + return &((struct udphdr *)txporthdr)->check; + + return NULL; +} + +static int +rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, + struct rmnet_map_dl_csum_trailer *csum_trailer, + struct rmnet_priv *priv) +{ + struct iphdr *ip4h = (struct iphdr *)skb->data; + void *txporthdr = skb->data + ip4h->ihl * 4; + __sum16 *csum_field, pseudo_csum; + __sum16 ip_payload_csum; + + /* Computing the checksum over just the IPv4 header--including its + * checksum field--should yield 0. If it doesn't, the IP header + * is bad, so return an error and let the IP layer drop it. + */ + if (ip_fast_csum(ip4h, ip4h->ihl)) { + priv->stats.csum_ip4_header_bad++; + return -EINVAL; + } + + /* We don't support checksum offload on IPv4 fragments */ + if (ip_is_fragment(ip4h)) { + priv->stats.csum_fragmented_pkt++; + return -EOPNOTSUPP; + } + + /* Checksum offload is only supported for UDP and TCP protocols */ + csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr); + if (!csum_field) { + priv->stats.csum_err_invalid_transport++; + return -EPROTONOSUPPORT; + } + + /* RFC 768: UDP checksum is optional for IPv4, and is 0 if unused */ + if (!*csum_field && ip4h->protocol == IPPROTO_UDP) { + priv->stats.csum_skipped++; + return 0; + } + + /* The checksum value in the trailer is computed over the entire + * IP packet, including the IP header and payload. To derive the + * transport checksum from this, we first subract the contribution + * of the IP header from the trailer checksum. We then add the + * checksum computed over the pseudo header. + * + * We verified above that the IP header contributes zero to the + * trailer checksum. Therefore the checksum in the trailer is + * just the checksum computed over the IP payload. + + * If the IP payload arrives intact, adding the pseudo header + * checksum to the IP payload checksum will yield 0xffff (negative + * zero). This means the trailer checksum and the pseudo checksum + * are additive inverses of each other. Put another way, the + * message passes the checksum test if the trailer checksum value + * is the negated pseudo header checksum. + * + * Knowing this, we don't even need to examine the transport + * header checksum value; it is already accounted for in the + * checksum value found in the trailer. + */ + ip_payload_csum = csum_trailer->csum_value; + + pseudo_csum = csum_tcpudp_magic(ip4h->saddr, ip4h->daddr, + ntohs(ip4h->tot_len) - ip4h->ihl * 4, + ip4h->protocol, 0); + + /* The cast is required to ensure only the low 16 bits are examined */ + if (ip_payload_csum != (__sum16)~pseudo_csum) { + priv->stats.csum_validation_failed++; + return -EINVAL; + } + + priv->stats.csum_ok++; + return 0; +} + +#if IS_ENABLED(CONFIG_IPV6) +static int +rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, + struct rmnet_map_dl_csum_trailer *csum_trailer, + struct rmnet_priv *priv) +{ + struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data; + void *txporthdr = skb->data + sizeof(*ip6h); + __sum16 *csum_field, pseudo_csum; + __sum16 ip6_payload_csum; + __be16 ip_header_csum; + + /* Checksum offload is only supported for UDP and TCP protocols; + * the packet cannot include any IPv6 extension headers + */ + csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr); + if (!csum_field) { + priv->stats.csum_err_invalid_transport++; + return -EPROTONOSUPPORT; + } + + /* The checksum value in the trailer is computed over the entire + * IP packet, including the IP header and payload. To derive the + * transport checksum from this, we first subract the contribution + * of the IP header from the trailer checksum. We then add the + * checksum computed over the pseudo header. + */ + ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4); + ip6_payload_csum = csum16_sub(csum_trailer->csum_value, ip_header_csum); + + pseudo_csum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, + ntohs(ip6h->payload_len), + ip6h->nexthdr, 0); + + /* It's sufficient to compare the IP payload checksum with the + * negated pseudo checksum to determine whether the packet + * checksum was good. (See further explanation in comments + * in rmnet_map_ipv4_dl_csum_trailer()). + * + * The cast is required to ensure only the low 16 bits are + * examined. + */ + if (ip6_payload_csum != (__sum16)~pseudo_csum) { + priv->stats.csum_validation_failed++; + return -EINVAL; + } + + priv->stats.csum_ok++; + return 0; +} +#else +static int +rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, + struct rmnet_map_dl_csum_trailer *csum_trailer, + struct rmnet_priv *priv) +{ + return 0; +} +#endif + +static void rmnet_map_complement_ipv4_txporthdr_csum_field(struct iphdr *ip4h) +{ + void *txphdr; + u16 *csum; + + txphdr = (void *)ip4h + ip4h->ihl * 4; + + if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) { + csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr); + *csum = ~(*csum); + } +} + +static void +rmnet_map_ipv4_ul_csum_header(struct iphdr *iphdr, + struct rmnet_map_ul_csum_header *ul_header, + struct sk_buff *skb) +{ + u16 val; + + val = MAP_CSUM_UL_ENABLED_FLAG; + if (iphdr->protocol == IPPROTO_UDP) + val |= MAP_CSUM_UL_UDP_FLAG; + val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK; + + ul_header->csum_start_offset = htons(skb_network_header_len(skb)); + ul_header->csum_info = htons(val); + + skb->ip_summed = CHECKSUM_NONE; + + rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr); +} + +#if IS_ENABLED(CONFIG_IPV6) +static void +rmnet_map_complement_ipv6_txporthdr_csum_field(struct ipv6hdr *ip6h) +{ + void *txphdr; + u16 *csum; + + txphdr = ip6h + 1; + + if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) { + csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr); + *csum = ~(*csum); + } +} + +static void +rmnet_map_ipv6_ul_csum_header(struct ipv6hdr *ipv6hdr, + struct rmnet_map_ul_csum_header *ul_header, + struct sk_buff *skb) +{ + u16 val; + + val = MAP_CSUM_UL_ENABLED_FLAG; + if (ipv6hdr->nexthdr == IPPROTO_UDP) + val |= MAP_CSUM_UL_UDP_FLAG; + val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK; + + ul_header->csum_start_offset = htons(skb_network_header_len(skb)); + ul_header->csum_info = htons(val); + + skb->ip_summed = CHECKSUM_NONE; + + rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr); +} +#else +static void +rmnet_map_ipv6_ul_csum_header(void *ip6hdr, + struct rmnet_map_ul_csum_header *ul_header, + struct sk_buff *skb) +{ +} +#endif + +static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb, + struct rmnet_port *port, + struct net_device *orig_dev) +{ + struct rmnet_priv *priv = netdev_priv(orig_dev); + struct rmnet_map_v5_csum_header *ul_header; + + ul_header = skb_push(skb, sizeof(*ul_header)); + memset(ul_header, 0, sizeof(*ul_header)); + ul_header->header_info = u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD, + MAPV5_HDRINFO_HDR_TYPE_FMASK); + + if (skb->ip_summed == CHECKSUM_PARTIAL) { + void *iph = ip_hdr(skb); + __sum16 *check; + void *trans; + u8 proto; + + if (skb->protocol == htons(ETH_P_IP)) { + u16 ip_len = ((struct iphdr *)iph)->ihl * 4; + + proto = ((struct iphdr *)iph)->protocol; + trans = iph + ip_len; + } else if (IS_ENABLED(CONFIG_IPV6) && + skb->protocol == htons(ETH_P_IPV6)) { + u16 ip_len = sizeof(struct ipv6hdr); + + proto = ((struct ipv6hdr *)iph)->nexthdr; + trans = iph + ip_len; + } else { + priv->stats.csum_err_invalid_ip_version++; + goto sw_csum; + } + + check = rmnet_map_get_csum_field(proto, trans); + if (check) { + skb->ip_summed = CHECKSUM_NONE; + /* Ask for checksum offloading */ + ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG; + priv->stats.csum_hw++; + return; + } + } + +sw_csum: + priv->stats.csum_sw++; +} + +/* 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, + struct rmnet_port *port, + int pad) +{ + struct rmnet_map_header *map_header; + u32 padding, map_datalen; + + 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)); + + /* Set next_hdr bit for csum offload packets */ + if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5) + map_header->flags |= MAP_NEXT_HEADER_FLAG; + + if (pad == RMNET_MAP_NO_PAD_BYTES) { + map_header->pkt_len = htons(map_datalen); + return map_header; + } + + BUILD_BUG_ON(MAP_PAD_LEN_MASK < 3); + padding = ALIGN(map_datalen, 4) - map_datalen; + + if (padding == 0) + goto done; + + if (skb_tailroom(skb) < padding) + return NULL; + + skb_put_zero(skb, padding); + +done: + map_header->pkt_len = htons(map_datalen + padding); + /* This is a data packet, so the CMD bit is 0 */ + map_header->flags = padding & MAP_PAD_LEN_MASK; + + 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_port *port) +{ + struct rmnet_map_v5_csum_header *next_hdr = NULL; + struct rmnet_map_header *maph; + void *data = skb->data; + struct sk_buff *skbn; + u8 nexthdr_type; + u32 packet_len; + + if (skb->len == 0) + return NULL; + + maph = (struct rmnet_map_header *)skb->data; + packet_len = ntohs(maph->pkt_len) + sizeof(*maph); + + if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) { + packet_len += sizeof(struct rmnet_map_dl_csum_trailer); + } else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) { + if (!(maph->flags & MAP_CMD_FLAG)) { + packet_len += sizeof(*next_hdr); + if (maph->flags & MAP_NEXT_HEADER_FLAG) + next_hdr = data + sizeof(*maph); + else + /* Mapv5 data pkt without csum hdr is invalid */ + return NULL; + } + } + + if (((int)skb->len - (int)packet_len) < 0) + return NULL; + + /* Some hardware can send us empty frames. Catch them */ + if (!maph->pkt_len) + return NULL; + + if (next_hdr) { + nexthdr_type = u8_get_bits(next_hdr->header_info, + MAPV5_HDRINFO_HDR_TYPE_FMASK); + if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) + return NULL; + } + + skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC); + if (!skbn) + return NULL; + + skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM); + skb_put(skbn, packet_len); + memcpy(skbn->data, skb->data, packet_len); + skb_pull(skb, packet_len); + + return skbn; +} + +/* Validates packet checksums. Function takes a pointer to + * the beginning of a buffer which contains the IP payload + + * padding + checksum trailer. + * Only IPv4 and IPv6 are supported along with TCP & UDP. + * Fragmented or tunneled packets are not supported. + */ +int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len) +{ + struct rmnet_priv *priv = netdev_priv(skb->dev); + struct rmnet_map_dl_csum_trailer *csum_trailer; + + if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) { + priv->stats.csum_sw++; + return -EOPNOTSUPP; + } + + csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len); + + if (!(csum_trailer->flags & MAP_CSUM_DL_VALID_FLAG)) { + priv->stats.csum_valid_unset++; + return -EINVAL; + } + + if (skb->protocol == htons(ETH_P_IP)) + return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv); + + if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) + return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv); + + priv->stats.csum_err_invalid_ip_version++; + + return -EPROTONOSUPPORT; +} + +static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb, + struct net_device *orig_dev) +{ + struct rmnet_priv *priv = netdev_priv(orig_dev); + struct rmnet_map_ul_csum_header *ul_header; + void *iphdr; + + ul_header = (struct rmnet_map_ul_csum_header *) + skb_push(skb, sizeof(struct rmnet_map_ul_csum_header)); + + if (unlikely(!(orig_dev->features & + (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)))) + goto sw_csum; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + goto sw_csum; + + iphdr = (char *)ul_header + + sizeof(struct rmnet_map_ul_csum_header); + + if (skb->protocol == htons(ETH_P_IP)) { + rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb); + priv->stats.csum_hw++; + return; + } + + if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { + rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb); + priv->stats.csum_hw++; + return; + } + + priv->stats.csum_err_invalid_ip_version++; + +sw_csum: + memset(ul_header, 0, sizeof(*ul_header)); + + priv->stats.csum_sw++; +} + +/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP + * packets that are supported for UL checksum offload. + */ +void rmnet_map_checksum_uplink_packet(struct sk_buff *skb, + struct rmnet_port *port, + struct net_device *orig_dev, + int csum_type) +{ + switch (csum_type) { + case RMNET_FLAGS_EGRESS_MAP_CKSUMV4: + rmnet_map_v4_checksum_uplink_packet(skb, orig_dev); + break; + case RMNET_FLAGS_EGRESS_MAP_CKSUMV5: + rmnet_map_v5_checksum_uplink_packet(skb, port, orig_dev); + break; + default: + break; + } +} + +/* Process a MAPv5 packet header */ +int rmnet_map_process_next_hdr_packet(struct sk_buff *skb, + u16 len) +{ + struct rmnet_priv *priv = netdev_priv(skb->dev); + struct rmnet_map_v5_csum_header *next_hdr; + u8 nexthdr_type; + + next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data + + sizeof(struct rmnet_map_header)); + + nexthdr_type = u8_get_bits(next_hdr->header_info, + MAPV5_HDRINFO_HDR_TYPE_FMASK); + + if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) + return -EINVAL; + + if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) { + priv->stats.csum_sw++; + } else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) { + priv->stats.csum_ok++; + skb->ip_summed = CHECKSUM_UNNECESSARY; + } else { + priv->stats.csum_valid_unset++; + } + + /* Pull csum v5 header */ + skb_pull(skb, sizeof(*next_hdr)); + + return 0; +} |