net: pppoe: implement GRO/GSO support

Only handles packets where the pppoe header length field matches the exact
packet length. Significantly improves rx throughput.

When running NAT traffic through a MediaTek MT7621 devices from a host
behind PPPoE to a host directly connected via ethernet, the TCP throughput
that the device is able to handle improves from ~130 Mbit/s to ~630 Mbit/s,
using fraglist GRO.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
Tested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Link: https://patch.msgid.link/20260513013400.7467-1-qingfang.deng@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index ad5bb98c15794b9d02b207531f404cc23158d693..4a018acb52628c0717a8ff897c0abafca717e768 100644 (file)
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -77,6 +77,7 @@
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
 #include <net/sock.h>
+#include <net/gro.h>
 
 #include <linux/uaccess.h>
 
@@ -409,7 +410,7 @@ static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
        if (ppp_skb_is_compressed_proto(skb))
                goto drop;
 
-       if (pskb_trim_rcsum(skb, len))
+       if (!skb_is_gso(skb) && pskb_trim_rcsum(skb, len))
                goto drop;
 
        ph = pppoe_hdr(skb);
@@ -1103,6 +1104,160 @@ static struct pernet_operations pppoe_net_ops = {
        .size = sizeof(struct pppoe_net),
 };
 
+static u16
+compare_pppoe_header(const struct pppoe_hdr *phdr,
+                    const struct pppoe_hdr *phdr2)
+{
+       __be16 proto = *(const __be16 *)(phdr + 1);
+       __be16 proto2 = *(const __be16 *)(phdr2 + 1);
+
+       return (__force u16)((phdr->sid ^ phdr2->sid) | (proto ^ proto2));
+}
+
+static __be16 pppoe_hdr_proto(const struct pppoe_hdr *phdr)
+{
+       __be16 proto = *(const __be16 *)(phdr + 1);
+
+       switch (proto) {
+       case cpu_to_be16(PPP_IP):
+               return cpu_to_be16(ETH_P_IP);
+#if IS_ENABLED(CONFIG_IPV6)
+       case cpu_to_be16(PPP_IPV6):
+               return cpu_to_be16(ETH_P_IPV6);
+#endif
+       default:
+               return 0;
+       }
+}
+
+static struct sk_buff *pppoe_gro_receive(struct list_head *head,
+                                        struct sk_buff *skb)
+{
+       const struct packet_offload *ptype;
+       unsigned int hlen, off_pppoe;
+       const struct pppoe_hdr *phdr;
+       struct sk_buff *pp = NULL;
+       struct sk_buff *p;
+       int flush = 1;
+       __be16 type;
+
+       off_pppoe = skb_gro_offset(skb);
+       hlen = off_pppoe + PPPOE_SES_HLEN;
+       phdr = skb_gro_header(skb, hlen, off_pppoe);
+       if (unlikely(!phdr))
+               goto out;
+
+       /* filter for session packets (type:1, ver:1, code:0) */
+       if (*(const __be16 *)phdr != cpu_to_be16(0x1100))
+               goto out;
+
+       /* ignore packets with padding or invalid length */
+       if (skb_gro_len(skb) != be16_to_cpu(phdr->length) + sizeof(*phdr))
+               goto out;
+
+       type = pppoe_hdr_proto(phdr);
+       ptype = gro_find_receive_by_type(type);
+       if (!ptype)
+               goto out;
+
+       flush = 0;
+
+       list_for_each_entry(p, head, list) {
+               const struct pppoe_hdr *phdr2;
+
+               if (!NAPI_GRO_CB(p)->same_flow)
+                       continue;
+
+               phdr2 = (const struct pppoe_hdr *)(p->data + off_pppoe);
+               if (compare_pppoe_header(phdr, phdr2))
+                       NAPI_GRO_CB(p)->same_flow = 0;
+       }
+
+       skb_gro_pull(skb, PPPOE_SES_HLEN);
+       skb_gro_postpull_rcsum(skb, phdr, PPPOE_SES_HLEN);
+
+       pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
+                                           ipv6_gro_receive, inet_gro_receive,
+                                           head, skb);
+
+out:
+       skb_gro_flush_final(skb, pp, flush);
+
+       return pp;
+}
+
+static int pppoe_gro_complete(struct sk_buff *skb, int nhoff)
+{
+       struct pppoe_hdr *phdr = (struct pppoe_hdr *)(skb->data + nhoff);
+       __be16 type = pppoe_hdr_proto(phdr);
+       struct packet_offload *ptype;
+       unsigned int len;
+
+       ptype = gro_find_complete_by_type(type);
+       if (!ptype)
+               return -ENOENT;
+
+       len = skb->len - (nhoff + sizeof(*phdr));
+       len = min(len, 0xFFFFU);
+       phdr->length = cpu_to_be16(len);
+
+       return INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
+                                 ipv6_gro_complete, inet_gro_complete,
+                                 skb, nhoff + PPPOE_SES_HLEN);
+}
+
+static struct sk_buff *pppoe_gso_segment(struct sk_buff *skb,
+                                        netdev_features_t features)
+{
+       struct sk_buff *segs = ERR_PTR(-EINVAL);
+       struct packet_offload *ptype;
+       struct pppoe_hdr *phdr;
+       __be16 orig_type, type;
+       int len, nhoff;
+
+       skb_reset_network_header(skb);
+       nhoff = skb_network_header(skb) - skb_mac_header(skb);
+
+       if (unlikely(!pskb_may_pull(skb, PPPOE_SES_HLEN)))
+               goto out;
+
+       phdr = (struct pppoe_hdr *)skb_network_header(skb);
+       type = pppoe_hdr_proto(phdr);
+       ptype = gro_find_complete_by_type(type);
+       if (!ptype)
+               goto out;
+
+       orig_type = skb->protocol;
+       __skb_pull(skb, PPPOE_SES_HLEN);
+       features &= ~NETIF_F_GSO_SOFTWARE;
+       segs = ptype->callbacks.gso_segment(skb, features);
+       if (IS_ERR_OR_NULL(segs))
+               goto out;
+
+       skb = segs;
+       do {
+               phdr = (struct pppoe_hdr *)(skb_mac_header(skb) + nhoff);
+               len = skb->len - (nhoff + sizeof(*phdr));
+               phdr->length = cpu_to_be16(len);
+               skb->network_header = (u8 *)phdr - skb->head;
+               skb->protocol = orig_type;
+               skb_reset_mac_len(skb);
+       } while ((skb = skb->next));
+
+out:
+       return segs;
+}
+
+static struct packet_offload pppoe_packet_offload __read_mostly = {
+       .type = cpu_to_be16(ETH_P_PPP_SES),
+       .priority = 20,
+       .callbacks = {
+               .gro_receive = pppoe_gro_receive,
+               .gro_complete = pppoe_gro_complete,
+               .gso_segment = pppoe_gso_segment,
+       },
+};
+
 static int __init pppoe_init(void)
 {
        int err;
@@ -1119,6 +1274,8 @@ static int __init pppoe_init(void)
        if (err)
                goto out_unregister_pppoe_proto;
 
+       if (IS_ENABLED(CONFIG_INET))
+               dev_add_offload(&pppoe_packet_offload);
        dev_add_pack(&pppoes_ptype);
        dev_add_pack(&pppoed_ptype);
        register_netdevice_notifier(&pppoe_notifier);
@@ -1138,6 +1295,8 @@ static void __exit pppoe_exit(void)
        unregister_netdevice_notifier(&pppoe_notifier);
        dev_remove_pack(&pppoed_ptype);
        dev_remove_pack(&pppoes_ptype);
+       if (IS_ENABLED(CONFIG_INET))
+               dev_remove_offload(&pppoe_packet_offload);
        unregister_pppox_proto(PX_PROTO_OE);
        proto_unregister(&pppoe_sk_proto);
        unregister_pernet_device(&pppoe_net_ops);

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 0e62032e76b19b3b5616110bf49194d3afe62f92..cbac072633bb57fd68131904fa3eff24265696d9 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1540,6 +1540,7 @@ out:
 
        return pp;
 }
+EXPORT_INDIRECT_CALLABLE(inet_gro_receive);
 
 static struct sk_buff *ipip_gro_receive(struct list_head *head,
                                        struct sk_buff *skb)
@@ -1625,6 +1626,7 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff)
 out:
        return err;
 }
+EXPORT_INDIRECT_CALLABLE(inet_gro_complete);
 
 static int ipip_gro_complete(struct sk_buff *skb, int nhoff)
 {

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index d8072ad6b8c4a5135dece2cfe465445bb9f8ce8c..78f50c93c536cc7d6d9d4cff5cea18273ec51a6a 100644 (file)
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -297,6 +297,7 @@ out:
 
        return pp;
 }
+EXPORT_INDIRECT_CALLABLE(ipv6_gro_receive);
 
 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
                                              struct sk_buff *skb)
@@ -359,6 +360,7 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 out:
        return err;
 }
+EXPORT_INDIRECT_CALLABLE(ipv6_gro_complete);
 
 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 {