Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / net / udplite.h

diff --git a/kernel/include/net/udplite.h b/kernel/include/net/udplite.h
new file mode 100644 (file)
index 0000000..8076193
--- /dev/null
+++ b/kernel/include/net/udplite.h
@@ -0,0 +1,133 @@
+/*
+ *     Definitions for the UDP-Lite (RFC 3828) code.
+ */
+#ifndef _UDPLITE_H
+#define _UDPLITE_H
+
+#include <net/ip6_checksum.h>
+
+/* UDP-Lite socket options */
+#define UDPLITE_SEND_CSCOV   10 /* sender partial coverage (as sent)      */
+#define UDPLITE_RECV_CSCOV   11 /* receiver partial coverage (threshold ) */
+
+extern struct proto            udplite_prot;
+extern struct udp_table                udplite_table;
+
+/*
+ *     Checksum computation is all in software, hence simpler getfrag.
+ */
+static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
+                                     int len, int odd, struct sk_buff *skb)
+{
+       struct msghdr *msg = from;
+       return copy_from_iter(to, len, &msg->msg_iter) != len ? -EFAULT : 0;
+}
+
+/* Designate sk as UDP-Lite socket */
+static inline int udplite_sk_init(struct sock *sk)
+{
+       udp_sk(sk)->pcflag = UDPLITE_BIT;
+       return 0;
+}
+
+/*
+ *     Checksumming routines
+ */
+static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+       u16 cscov;
+
+        /* In UDPv4 a zero checksum means that the transmitter generated no
+         * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
+         * with a zero checksum field are illegal.                            */
+       if (uh->check == 0) {
+               net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
+               return 1;
+       }
+
+       cscov = ntohs(uh->len);
+
+       if (cscov == 0)          /* Indicates that full coverage is required. */
+               ;
+       else if (cscov < 8  || cscov > skb->len) {
+               /*
+                * Coverage length violates RFC 3828: log and discard silently.
+                */
+               net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
+                                   cscov, skb->len);
+               return 1;
+
+       } else if (cscov < skb->len) {
+               UDP_SKB_CB(skb)->partial_cov = 1;
+               UDP_SKB_CB(skb)->cscov = cscov;
+               if (skb->ip_summed == CHECKSUM_COMPLETE)
+                       skb->ip_summed = CHECKSUM_NONE;
+        }
+
+       return 0;
+}
+
+/* Slow-path computation of checksum. Socket is locked. */
+static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
+{
+       const struct udp_sock *up = udp_sk(skb->sk);
+       int cscov = up->len;
+       __wsum csum = 0;
+
+       if (up->pcflag & UDPLITE_SEND_CC) {
+               /*
+                * Sender has set `partial coverage' option on UDP-Lite socket.
+                * The special case "up->pcslen == 0" signifies full coverage.
+                */
+               if (up->pcslen < up->len) {
+                       if (0 < up->pcslen)
+                               cscov = up->pcslen;
+                       udp_hdr(skb)->len = htons(up->pcslen);
+               }
+               /*
+                * NOTE: Causes for the error case  `up->pcslen > up->len':
+                *        (i)  Application error (will not be penalized).
+                *       (ii)  Payload too big for send buffer: data is split
+                *             into several packets, each with its own header.
+                *             In this case (e.g. last segment), coverage may
+                *             exceed packet length.
+                *       Since packets with coverage length > packet length are
+                *       illegal, we fall back to the defaults here.
+                */
+       }
+
+       skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
+
+       skb_queue_walk(&sk->sk_write_queue, skb) {
+               const int off = skb_transport_offset(skb);
+               const int len = skb->len - off;
+
+               csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
+
+               if ((cscov -= len) <= 0)
+                       break;
+       }
+       return csum;
+}
+
+/* Fast-path computation of checksum. Socket may not be locked. */
+static inline __wsum udplite_csum(struct sk_buff *skb)
+{
+       const struct udp_sock *up = udp_sk(skb->sk);
+       const int off = skb_transport_offset(skb);
+       int len = skb->len - off;
+
+       if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
+               if (0 < up->pcslen)
+                       len = up->pcslen;
+               udp_hdr(skb)->len = htons(up->pcslen);
+       }
+       skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
+
+       return skb_checksum(skb, off, len, 0);
+}
+
+void udplite4_register(void);
+int udplite_get_port(struct sock *sk, unsigned short snum,
+                    int (*scmp)(const struct sock *, const struct sock *));
+#endif /* _UDPLITE_H */