@@ -45,6 +45,7 @@ struct inet_connection_sock_af_ops {
struct dst_entry *dst);
struct inet_peer *(*get_peer)(struct sock *sk, bool *release_it);
u16 net_header_len;
+ u16 net_frag_header_len;
u16 sockaddr_len;
int (*setsockopt)(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen);
@@ -531,8 +531,8 @@ extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
extern void tcp_initialize_rcv_mss(struct sock *sk);
-extern int tcp_mtu_to_mss(const struct sock *sk, int pmtu);
-extern int tcp_mss_to_mtu(const struct sock *sk, int mss);
+extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
+extern int tcp_mss_to_mtu(struct sock *sk, int mss);
extern void tcp_mtup_init(struct sock *sk);
extern void tcp_valid_rtt_meas(struct sock *sk, u32 seq_rtt);
@@ -1151,7 +1151,7 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
}
/* Calculate MSS. Not accounting for SACKs here. */
-int tcp_mtu_to_mss(const struct sock *sk, int pmtu)
+int tcp_mtu_to_mss(struct sock *sk, int pmtu)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1162,6 +1162,14 @@ int tcp_mtu_to_mss(const struct sock *sk, int pmtu)
*/
mss_now = pmtu - icsk->icsk_af_ops->net_header_len - sizeof(struct tcphdr);
+ /* IPv6 adds a frag_hdr in case RTAX_FEATURE_ALLFRAG is set */
+ if (icsk->icsk_af_ops->net_frag_header_len) {
+ const struct dst_entry *dst = __sk_dst_get(sk);
+
+ if (dst && dst_allfrag(dst))
+ mss_now -= icsk->icsk_af_ops->net_frag_header_len;
+ }
+
/* Clamp it (mss_clamp does not include tcp options) */
if (mss_now > tp->rx_opt.mss_clamp)
mss_now = tp->rx_opt.mss_clamp;
@@ -1180,7 +1188,7 @@ int tcp_mtu_to_mss(const struct sock *sk, int pmtu)
}
/* Inverse of above */
-int tcp_mss_to_mtu(const struct sock *sk, int mss)
+int tcp_mss_to_mtu(struct sock *sk, int mss)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1191,6 +1199,13 @@ int tcp_mss_to_mtu(const struct sock *sk, int mss)
icsk->icsk_ext_hdr_len +
icsk->icsk_af_ops->net_header_len;
+ /* IPv6 adds a frag_hdr in case RTAX_FEATURE_ALLFRAG is set */
+ if (icsk->icsk_af_ops->net_frag_header_len) {
+ const struct dst_entry *dst = __sk_dst_get(sk);
+
+ if (dst && dst_allfrag(dst))
+ mtu += icsk->icsk_af_ops->net_frag_header_len;
+ }
return mtu;
}
@@ -1883,6 +1883,7 @@ static const struct inet_connection_sock_af_ops ipv6_specific = {
.syn_recv_sock = tcp_v6_syn_recv_sock,
.get_peer = tcp_v6_get_peer,
.net_header_len = sizeof(struct ipv6hdr),
+ .net_frag_header_len = sizeof(struct frag_hdr),
.setsockopt = ipv6_setsockopt,
.getsockopt = ipv6_getsockopt,
.addr2sockaddr = inet6_csk_addr2sockaddr,
@@ -1000,6 +1000,7 @@ static struct sctp_af sctp_af_inet6 = {
.seq_dump_addr = sctp_v6_seq_dump_addr,
.ecn_capable = sctp_v6_ecn_capable,
.net_header_len = sizeof(struct ipv6hdr),
+ .net_frag_header_len = sizeof(struct frag_hdr),
.sockaddr_len = sizeof(struct sockaddr_in6),
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_ipv6_setsockopt,