net: Abstract default ADVMSS behind an accessor.
Make all RTAX_ADVMSS metric accesses go through a new helper function, dst_metric_advmss(). Leave the actual default metric as "zero" in the real metric slot, and compute the actual default value dynamically via a new dst_ops AF specific callback. For stacked IPSEC routes, we use the advmss of the path which preserves existing behavior. Unlike ipv4/ipv6, DecNET ties the advmss to the mtu and thus updates advmss on pmtu updates. This inconsistency in advmss handling results in more raw metric accesses than I wish we ended up with. Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
Родитель
cc6f02dd49
Коммит
0dbaee3b37
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@ -825,7 +825,7 @@ unsigned int cxgbi_sock_select_mss(struct cxgbi_sock *csk, unsigned int pmtu)
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unsigned int idx;
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struct dst_entry *dst = csk->dst;
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csk->advmss = dst_metric(dst, RTAX_ADVMSS);
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csk->advmss = dst_metric_advmss(dst);
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if (csk->advmss > pmtu - 40)
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csk->advmss = pmtu - 40;
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@ -112,10 +112,22 @@ dst_metric_raw(const struct dst_entry *dst, const int metric)
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static inline u32
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dst_metric(const struct dst_entry *dst, const int metric)
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{
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WARN_ON_ONCE(metric == RTAX_HOPLIMIT);
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WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
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metric == RTAX_ADVMSS);
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return dst_metric_raw(dst, metric);
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}
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static inline u32
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dst_metric_advmss(const struct dst_entry *dst)
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{
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u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
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if (!advmss)
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advmss = dst->ops->default_advmss(dst);
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return advmss;
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}
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static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
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{
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dst->_metrics[metric-1] = val;
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@ -16,6 +16,7 @@ struct dst_ops {
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int (*gc)(struct dst_ops *ops);
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struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
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unsigned int (*default_advmss)(const struct dst_entry *);
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void (*destroy)(struct dst_entry *);
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void (*ifdown)(struct dst_entry *,
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struct net_device *dev, int how);
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@ -829,7 +829,7 @@ static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
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return -EINVAL;
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scp->state = DN_CC;
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scp->segsize_loc = dst_metric(__sk_dst_get(sk), RTAX_ADVMSS);
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scp->segsize_loc = dst_metric_advmss(__sk_dst_get(sk));
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dn_send_conn_conf(sk, allocation);
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prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
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@ -958,7 +958,7 @@ static int __dn_connect(struct sock *sk, struct sockaddr_dn *addr, int addrlen,
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sk->sk_route_caps = sk->sk_dst_cache->dev->features;
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sock->state = SS_CONNECTING;
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scp->state = DN_CI;
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scp->segsize_loc = dst_metric(sk->sk_dst_cache, RTAX_ADVMSS);
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scp->segsize_loc = dst_metric_advmss(sk->sk_dst_cache);
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dn_nsp_send_conninit(sk, NSP_CI);
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err = -EINPROGRESS;
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@ -110,6 +110,7 @@ static unsigned long dn_rt_deadline;
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static int dn_dst_gc(struct dst_ops *ops);
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static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
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static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
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static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
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static void dn_dst_link_failure(struct sk_buff *);
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static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
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@ -129,6 +130,7 @@ static struct dst_ops dn_dst_ops = {
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.gc_thresh = 128,
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.gc = dn_dst_gc,
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.check = dn_dst_check,
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.default_advmss = dn_dst_default_advmss,
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.negative_advice = dn_dst_negative_advice,
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.link_failure = dn_dst_link_failure,
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.update_pmtu = dn_dst_update_pmtu,
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@ -245,7 +247,8 @@ static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
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}
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if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
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u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
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if (dst_metric(dst, RTAX_ADVMSS) > mss)
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u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
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if (!existing_mss || existing_mss > mss)
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dst_metric_set(dst, RTAX_ADVMSS, mss);
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}
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}
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@ -795,12 +798,17 @@ static int dn_rt_bug(struct sk_buff *skb)
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return NET_RX_DROP;
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}
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static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
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{
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return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
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}
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static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
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{
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struct dn_fib_info *fi = res->fi;
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struct net_device *dev = rt->dst.dev;
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struct neighbour *n;
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unsigned mss;
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unsigned int metric;
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if (fi) {
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if (DN_FIB_RES_GW(*res) &&
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@ -820,10 +828,12 @@ static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
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if (dst_metric(&rt->dst, RTAX_MTU) == 0 ||
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dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
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dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
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mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
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if (dst_metric(&rt->dst, RTAX_ADVMSS) == 0 ||
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dst_metric(&rt->dst, RTAX_ADVMSS) > mss)
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dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
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metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
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if (metric) {
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unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
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if (metric > mss)
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dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
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}
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return 0;
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}
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@ -139,6 +139,7 @@ static unsigned long expires_ljiffies;
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*/
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static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
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static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
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static void ipv4_dst_destroy(struct dst_entry *dst);
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static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
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static void ipv4_link_failure(struct sk_buff *skb);
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@ -155,6 +156,7 @@ static struct dst_ops ipv4_dst_ops = {
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.protocol = cpu_to_be16(ETH_P_IP),
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.gc = rt_garbage_collect,
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.check = ipv4_dst_check,
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.default_advmss = ipv4_default_advmss,
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.destroy = ipv4_dst_destroy,
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.ifdown = ipv4_dst_ifdown,
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.negative_advice = ipv4_negative_advice,
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@ -383,8 +385,7 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
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(__force u32)r->rt_gateway,
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r->rt_flags, atomic_read(&r->dst.__refcnt),
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r->dst.__use, 0, (__force u32)r->rt_src,
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(dst_metric(&r->dst, RTAX_ADVMSS) ?
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(int)dst_metric(&r->dst, RTAX_ADVMSS) + 40 : 0),
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dst_metric_advmss(&r->dst) + 40,
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dst_metric(&r->dst, RTAX_WINDOW),
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(int)((dst_metric(&r->dst, RTAX_RTT) >> 3) +
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dst_metric(&r->dst, RTAX_RTTVAR)),
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@ -1798,6 +1799,19 @@ static void set_class_tag(struct rtable *rt, u32 tag)
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}
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#endif
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static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
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{
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unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
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if (advmss == 0) {
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advmss = max_t(unsigned int, dst->dev->mtu - 40,
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ip_rt_min_advmss);
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if (advmss > 65535 - 40)
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advmss = 65535 - 40;
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}
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return advmss;
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}
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static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
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{
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struct dst_entry *dst = &rt->dst;
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@ -1823,11 +1837,7 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
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if (dst_mtu(dst) > IP_MAX_MTU)
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dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
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if (dst_metric(dst, RTAX_ADVMSS) == 0)
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dst_metric_set(dst, RTAX_ADVMSS,
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max_t(unsigned int, dst->dev->mtu - 40,
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ip_rt_min_advmss));
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if (dst_metric(dst, RTAX_ADVMSS) > 65535 - 40)
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if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40)
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dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40);
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#ifdef CONFIG_NET_CLS_ROUTE
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@ -1436,7 +1436,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
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tcp_mtup_init(newsk);
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tcp_sync_mss(newsk, dst_mtu(dst));
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newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
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newtp->advmss = dst_metric_advmss(dst);
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if (tcp_sk(sk)->rx_opt.user_mss &&
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tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
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newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
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@ -119,9 +119,13 @@ static __u16 tcp_advertise_mss(struct sock *sk)
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struct dst_entry *dst = __sk_dst_get(sk);
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int mss = tp->advmss;
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if (dst && dst_metric(dst, RTAX_ADVMSS) < mss) {
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mss = dst_metric(dst, RTAX_ADVMSS);
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tp->advmss = mss;
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if (dst) {
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unsigned int metric = dst_metric_advmss(dst);
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if (metric < mss) {
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mss = metric;
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tp->advmss = mss;
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}
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}
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return (__u16)mss;
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@ -2422,7 +2426,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
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skb_dst_set(skb, dst_clone(dst));
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mss = dst_metric(dst, RTAX_ADVMSS);
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mss = dst_metric_advmss(dst);
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if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss)
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mss = tp->rx_opt.user_mss;
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@ -2556,7 +2560,7 @@ static void tcp_connect_init(struct sock *sk)
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if (!tp->window_clamp)
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tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
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tp->advmss = dst_metric(dst, RTAX_ADVMSS);
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tp->advmss = dst_metric_advmss(dst);
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if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < tp->advmss)
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tp->advmss = tp->rx_opt.user_mss;
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@ -76,6 +76,7 @@
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static struct rt6_info * ip6_rt_copy(struct rt6_info *ort);
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static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
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static unsigned int ip6_default_advmss(const struct dst_entry *dst);
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static struct dst_entry *ip6_negative_advice(struct dst_entry *);
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static void ip6_dst_destroy(struct dst_entry *);
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static void ip6_dst_ifdown(struct dst_entry *,
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@ -103,6 +104,7 @@ static struct dst_ops ip6_dst_ops_template = {
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.gc = ip6_dst_gc,
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.gc_thresh = 1024,
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.check = ip6_dst_check,
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.default_advmss = ip6_default_advmss,
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.destroy = ip6_dst_destroy,
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.ifdown = ip6_dst_ifdown,
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.negative_advice = ip6_negative_advice,
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@ -937,8 +939,12 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
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static int ipv6_get_mtu(struct net_device *dev);
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static inline unsigned int ipv6_advmss(struct net *net, unsigned int mtu)
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static unsigned int ip6_default_advmss(const struct dst_entry *dst)
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{
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struct net_device *dev = dst->dev;
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unsigned int mtu = dst_mtu(dst);
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struct net *net = dev_net(dev);
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mtu -= sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
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if (mtu < net->ipv6.sysctl.ip6_rt_min_advmss)
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@ -990,7 +996,6 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
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atomic_set(&rt->dst.__refcnt, 1);
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dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 255);
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dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev));
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dst_metric_set(&rt->dst, RTAX_ADVMSS, ipv6_advmss(net, dst_mtu(&rt->dst)));
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rt->dst.output = ip6_output;
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#if 0 /* there's no chance to use these for ndisc */
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@ -1312,8 +1317,6 @@ install_route:
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if (!dst_mtu(&rt->dst))
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dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(dev));
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if (!dst_metric(&rt->dst, RTAX_ADVMSS))
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dst_metric_set(&rt->dst, RTAX_ADVMSS, ipv6_advmss(net, dst_mtu(&rt->dst)));
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rt->dst.dev = dev;
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rt->rt6i_idev = idev;
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rt->rt6i_table = table;
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@ -1540,8 +1543,6 @@ void rt6_redirect(struct in6_addr *dest, struct in6_addr *src,
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nrt->rt6i_nexthop = neigh_clone(neigh);
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/* Reset pmtu, it may be better */
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dst_metric_set(&nrt->dst, RTAX_MTU, ipv6_get_mtu(neigh->dev));
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dst_metric_set(&nrt->dst, RTAX_ADVMSS, ipv6_advmss(dev_net(neigh->dev),
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dst_mtu(&nrt->dst)));
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if (ip6_ins_rt(nrt))
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goto out;
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@ -1971,7 +1972,6 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
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rt->rt6i_dev = net->loopback_dev;
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rt->rt6i_idev = idev;
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dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev));
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dst_metric_set(&rt->dst, RTAX_ADVMSS, ipv6_advmss(net, dst_mtu(&rt->dst)));
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dst_metric_set(&rt->dst, RTAX_HOPLIMIT, -1);
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rt->dst.obsolete = -1;
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@ -2041,7 +2041,6 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg)
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{
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struct rt6_mtu_change_arg *arg = (struct rt6_mtu_change_arg *) p_arg;
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struct inet6_dev *idev;
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struct net *net = dev_net(arg->dev);
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/* In IPv6 pmtu discovery is not optional,
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so that RTAX_MTU lock cannot disable it.
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@ -2073,7 +2072,6 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg)
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(dst_mtu(&rt->dst) < arg->mtu &&
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dst_mtu(&rt->dst) == idev->cnf.mtu6))) {
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dst_metric_set(&rt->dst, RTAX_MTU, arg->mtu);
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dst_metric_set(&rt->dst, RTAX_ADVMSS, ipv6_advmss(net, arg->mtu));
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}
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return 0;
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}
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@ -1521,7 +1521,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
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tcp_mtup_init(newsk);
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tcp_sync_mss(newsk, dst_mtu(dst));
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newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
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newtp->advmss = dst_metric_advmss(dst);
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tcp_initialize_rcv_mss(newsk);
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newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
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@ -2361,6 +2361,11 @@ static int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
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return 1;
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}
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static unsigned int xfrm_default_advmss(const struct dst_entry *dst)
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{
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return dst_metric_advmss(dst->path);
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}
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int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
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{
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struct net *net;
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@ -2378,6 +2383,8 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
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dst_ops->kmem_cachep = xfrm_dst_cache;
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if (likely(dst_ops->check == NULL))
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dst_ops->check = xfrm_dst_check;
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if (likely(dst_ops->default_advmss == NULL))
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dst_ops->default_advmss = xfrm_default_advmss;
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if (likely(dst_ops->negative_advice == NULL))
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dst_ops->negative_advice = xfrm_negative_advice;
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if (likely(dst_ops->link_failure == NULL))
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Загрузка…
Ссылка в новой задаче