net: udp4: move GSO functions to udp_offload

Similarly to TCP offloading and UDPv6 offloading, move all related
UDPv4 functions to udp_offload.c to make things more explicit. Also,
by this, we can make those functions static.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 104 insertions, 82 deletions

diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 4d3e138c564f..7fcf8101d85f 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -9,7 +9,7 @@ obj-y     := route.o inetpeer.o protocol.o \
              tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
              tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \
              tcp_offload.o datagram.o raw.o udp.o udplite.o \
-             arp.o icmp.o devinet.o af_inet.o  igmp.o \
+             udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
              fib_frontend.o fib_semantics.o fib_trie.o \
              inet_fragment.o ping.o
 
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 7b514290efc6..5598b06d62db 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1566,13 +1566,6 @@ static const struct net_protocol udp_protocol = {
         .netns_ok =     1,
 };
 
-static const struct net_offload udp_offload = {
-        .callbacks = {
-                .gso_send_check = udp4_ufo_send_check,
-                .gso_segment = udp4_ufo_fragment,
-        },
-};
-
 static const struct net_protocol icmp_protocol = {
         .handler =      icmp_rcv,
         .err_handler =  icmp_err,
@@ -1672,7 +1665,7 @@ static int __init ipv4_offload_init(void)
         /*
          * Add offloads
          */
-        if (inet_add_offload(&udp_offload, IPPROTO_UDP) < 0)
+        if (udpv4_offload_init() < 0)
                 pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
         if (tcpv4_offload_init() < 0)
                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2955b25aee6d..f65bc32c0266 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2290,29 +2290,8 @@ void __init udp_init(void)
         sysctl_udp_wmem_min = SK_MEM_QUANTUM;
 }
 
-int udp4_ufo_send_check(struct sk_buff *skb)
-{
-        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
-                return -EINVAL;
-
-        if (likely(!skb->encapsulation)) {
-                const struct iphdr *iph;
-                struct udphdr *uh;
-
-                iph = ip_hdr(skb);
-                uh = udp_hdr(skb);
-
-                uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
-                                IPPROTO_UDP, 0);
-                skb->csum_start = skb_transport_header(skb) - skb->head;
-                skb->csum_offset = offsetof(struct udphdr, check);
-                skb->ip_summed = CHECKSUM_PARTIAL;
-        }
-        return 0;
-}
-
-static struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
-                netdev_features_t features)
+struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
+                                       netdev_features_t features)
 {
         struct sk_buff *segs = ERR_PTR(-EINVAL);
         int mac_len = skb->mac_len;
@@ -2371,53 +2350,3 @@ static struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 out:
         return segs;
 }
-
-struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
-        netdev_features_t features)
-{
-        struct sk_buff *segs = ERR_PTR(-EINVAL);
-        unsigned int mss;
-        mss = skb_shinfo(skb)->gso_size;
-        if (unlikely(skb->len <= mss))
-                goto out;
-
-        if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
-                /* Packet is from an untrusted source, reset gso_segs. */
-                int type = skb_shinfo(skb)->gso_type;
-
-                if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
-                                      SKB_GSO_UDP_TUNNEL |
-                                      SKB_GSO_GRE | SKB_GSO_MPLS) ||
-                             !(type & (SKB_GSO_UDP))))
-                        goto out;
-
-                skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
-
-                segs = NULL;
-                goto out;
-        }
-
-        /* Fragment the skb. IP headers of the fragments are updated in
-         * inet_gso_segment()
-         */
-        if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
-                segs = skb_udp_tunnel_segment(skb, features);
-        else {
-                int offset;
-                __wsum csum;
-
-                /* Do software UFO. Complete and fill in the UDP checksum as
-                 * HW cannot do checksum of UDP packets sent as multiple
-                 * IP fragments.
-                 */
-                offset = skb_checksum_start_offset(skb);
-                csum = skb_checksum(skb, offset, skb->len - offset, 0);
-                offset += skb->csum_offset;
-                *(__sum16 *)(skb->data + offset) = csum_fold(csum);
-                skb->ip_summed = CHECKSUM_NONE;
-
-                segs = skb_segment(skb, features);
-        }
-out:
-        return segs;
-}
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
new file mode 100644
index 000000000000..f35eccaa855e
--- /dev/null
+++ b/net/ipv4/udp_offload.c
@@ -0,0 +1,100 @@
+/*
+ *      IPV4 GSO/GRO offload support
+ *      Linux INET implementation
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ *      UDPv4 GSO support
+ */
+
+#include <linux/skbuff.h>
+#include <net/udp.h>
+#include <net/protocol.h>
+
+static int udp4_ufo_send_check(struct sk_buff *skb)
+{
+        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+                return -EINVAL;
+
+        if (likely(!skb->encapsulation)) {
+                const struct iphdr *iph;
+                struct udphdr *uh;
+
+                iph = ip_hdr(skb);
+                uh = udp_hdr(skb);
+
+                uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
+                                IPPROTO_UDP, 0);
+                skb->csum_start = skb_transport_header(skb) - skb->head;
+                skb->csum_offset = offsetof(struct udphdr, check);
+                skb->ip_summed = CHECKSUM_PARTIAL;
+        }
+
+        return 0;
+}
+
+static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
+                                         netdev_features_t features)
+{
+        struct sk_buff *segs = ERR_PTR(-EINVAL);
+        unsigned int mss;
+
+        mss = skb_shinfo(skb)->gso_size;
+        if (unlikely(skb->len <= mss))
+                goto out;
+
+        if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+                /* Packet is from an untrusted source, reset gso_segs. */
+                int type = skb_shinfo(skb)->gso_type;
+
+                if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
+                                      SKB_GSO_UDP_TUNNEL |
+                                      SKB_GSO_GRE | SKB_GSO_MPLS) ||
+                             !(type & (SKB_GSO_UDP))))
+                        goto out;
+
+                skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
+
+                segs = NULL;
+                goto out;
+        }
+
+        /* Fragment the skb. IP headers of the fragments are updated in
+         * inet_gso_segment()
+         */
+        if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
+                segs = skb_udp_tunnel_segment(skb, features);
+        else {
+                int offset;
+                __wsum csum;
+
+                /* Do software UFO. Complete and fill in the UDP checksum as
+                 * HW cannot do checksum of UDP packets sent as multiple
+                 * IP fragments.
+                 */
+                offset = skb_checksum_start_offset(skb);
+                csum = skb_checksum(skb, offset, skb->len - offset, 0);
+                offset += skb->csum_offset;
+                *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+                skb->ip_summed = CHECKSUM_NONE;
+
+                segs = skb_segment(skb, features);
+        }
+out:
+        return segs;
+}
+
+static const struct net_offload udpv4_offload = {
+        .callbacks = {
+                .gso_send_check = udp4_ufo_send_check,
+                .gso_segment = udp4_ufo_fragment,
+        },
+};
+
+int __init udpv4_offload_init(void)
+{
+        return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
+}