| Message ID | 64341db6ca5a1f4d1eebbe86a7ee0b7d7400335e.1651071843.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | UDP/IPv6 refactoring | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/apply | fail | Patch does not apply to net-next |
On Thu, 2022-04-28 at 11:56 +0100, Pavel Begunkov wrote: > Users of ipcm6_init() have a somewhat complex post initialisation > of ->dontfrag and ->tclass. Not only it adds additional overhead, > but also complicates the code. > > First, replace ipcm6_init() with ipcm6_init_sk(). As it might be not an > equivalent change, let's first look at ->dontfrag. The logic was to set > it from cmsg if specified and otherwise fallback to np->dontfrag. Now > it's initialising to np->dontfrag in the beginning and then potentially > overriding with cmsg, which is absolutely the same behaviour. > > It's a bit more complex with ->tclass as ip6_datagram_send_ctl() might > set it to -1, which is a default and not valid value. The solution > here is to skip -1's specified in cmsg, so it'll be left with the socket > default value getting us to the old behaviour. > > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > include/net/ipv6.h | 9 --------- > net/ipv6/datagram.c | 4 ++-- > net/ipv6/ip6_output.c | 2 -- > net/ipv6/raw.c | 8 +------- > net/ipv6/udp.c | 7 +------ > net/l2tp/l2tp_ip6.c | 8 +------- > 6 files changed, 5 insertions(+), 33 deletions(-) > > diff --git a/include/net/ipv6.h b/include/net/ipv6.h > index 213612f1680c..30a3447e34b4 100644 > --- a/include/net/ipv6.h > +++ b/include/net/ipv6.h > @@ -352,15 +352,6 @@ struct ipcm6_cookie { > struct ipv6_txoptions *opt; > }; > > -static inline void ipcm6_init(struct ipcm6_cookie *ipc6) > -{ > - *ipc6 = (struct ipcm6_cookie) { > - .hlimit = -1, > - .tclass = -1, > - .dontfrag = -1, > - }; > -} > - > static inline void ipcm6_init_sk(struct ipcm6_cookie *ipc6, > const struct ipv6_pinfo *np) > { > diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c > index 206f66310a88..1b334bc855ae 100644 > --- a/net/ipv6/datagram.c > +++ b/net/ipv6/datagram.c > @@ -1003,9 +1003,9 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, > if (tc < -1 || tc > 0xff) > goto exit_f; > > + if (tc != -1) > + ipc6->tclass = tc; > err = 0; > - ipc6->tclass = tc; > - > break; > } It looks like the above causes a behavioral change: before this patch cmsg took precedence on socket status, after this patch looks like it's the opposide. Am I missing something? Thanks Paolo
On 4/28/22 15:04, Paolo Abeni wrote: > On Thu, 2022-04-28 at 11:56 +0100, Pavel Begunkov wrote: >> Users of ipcm6_init() have a somewhat complex post initialisation >> of ->dontfrag and ->tclass. Not only it adds additional overhead, >> but also complicates the code. >> >> First, replace ipcm6_init() with ipcm6_init_sk(). As it might be not an >> equivalent change, let's first look at ->dontfrag. The logic was to set >> it from cmsg if specified and otherwise fallback to np->dontfrag. Now >> it's initialising to np->dontfrag in the beginning and then potentially >> overriding with cmsg, which is absolutely the same behaviour. >> >> It's a bit more complex with ->tclass as ip6_datagram_send_ctl() might >> set it to -1, which is a default and not valid value. The solution >> here is to skip -1's specified in cmsg, so it'll be left with the socket >> default value getting us to the old behaviour. >> >> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >> --- >> include/net/ipv6.h | 9 --------- >> net/ipv6/datagram.c | 4 ++-- >> net/ipv6/ip6_output.c | 2 -- >> net/ipv6/raw.c | 8 +------- >> net/ipv6/udp.c | 7 +------ >> net/l2tp/l2tp_ip6.c | 8 +------- >> 6 files changed, 5 insertions(+), 33 deletions(-) >> >> diff --git a/include/net/ipv6.h b/include/net/ipv6.h >> index 213612f1680c..30a3447e34b4 100644 >> --- a/include/net/ipv6.h >> +++ b/include/net/ipv6.h >> @@ -352,15 +352,6 @@ struct ipcm6_cookie { >> struct ipv6_txoptions *opt; >> }; >> >> -static inline void ipcm6_init(struct ipcm6_cookie *ipc6) >> -{ >> - *ipc6 = (struct ipcm6_cookie) { >> - .hlimit = -1, >> - .tclass = -1, >> - .dontfrag = -1, >> - }; >> -} >> - >> static inline void ipcm6_init_sk(struct ipcm6_cookie *ipc6, >> const struct ipv6_pinfo *np) >> { >> diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c >> index 206f66310a88..1b334bc855ae 100644 >> --- a/net/ipv6/datagram.c >> +++ b/net/ipv6/datagram.c >> @@ -1003,9 +1003,9 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, >> if (tc < -1 || tc > 0xff) >> goto exit_f; >> >> + if (tc != -1) >> + ipc6->tclass = tc; >> err = 0; >> - ipc6->tclass = tc; >> - >> break; >> } > > It looks like the above causes a behavioral change: before this patch > cmsg took precedence on socket status, after this patch looks like it's > the opposide. > > Am I missing something? before: ipc6.tclass = -1; if (cmsg) ip6_datagram_send_ctl(&ipc6); if (ipc6.tclass < 0) ipc6.tclass = np->tclass; after: ipc6.tclass = np->tclass; // ipcm6_init_sk() if (cmsg) ip6_datagram_send_ctl(&ipc6); Both should prioritise cmsg. The only catch is when tclass is specified in cmsg but it's -1. The old version would assign np->tclass in the end, the new one does the same but with this added "if" in ip6_datagram_send_ctl() in the chunk you quoted. Unless I missed something as well.
diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 213612f1680c..30a3447e34b4 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -352,15 +352,6 @@ struct ipcm6_cookie { struct ipv6_txoptions *opt; }; -static inline void ipcm6_init(struct ipcm6_cookie *ipc6) -{ - *ipc6 = (struct ipcm6_cookie) { - .hlimit = -1, - .tclass = -1, - .dontfrag = -1, - }; -} - static inline void ipcm6_init_sk(struct ipcm6_cookie *ipc6, const struct ipv6_pinfo *np) { diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index 206f66310a88..1b334bc855ae 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -1003,9 +1003,9 @@ int ip6_datagram_send_ctl(struct net *net, struct sock *sk, if (tc < -1 || tc > 0xff) goto exit_f; + if (tc != -1) + ipc6->tclass = tc; err = 0; - ipc6->tclass = tc; - break; } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 1f3d777e7694..976554d0fdec 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -2001,8 +2001,6 @@ struct sk_buff *ip6_make_skb(struct sock *sk, ip6_cork_release(cork, &v6_cork); return ERR_PTR(err); } - if (ipc6->dontfrag < 0) - ipc6->dontfrag = inet6_sk(sk)->dontfrag; err = __ip6_append_data(sk, &queue, cork, &v6_cork, ¤t->task_frag, getfrag, from, diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 0d7c13d33d1a..4582e432fa9f 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -808,7 +808,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) fl6.flowi6_mark = sk->sk_mark; fl6.flowi6_uid = sk->sk_uid; - ipcm6_init(&ipc6); + ipcm6_init_sk(&ipc6, np); ipc6.sockc.tsflags = sk->sk_tsflags; ipc6.sockc.mark = sk->sk_mark; @@ -920,9 +920,6 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (hdrincl) fl6.flowi6_flags |= FLOWI_FLAG_KNOWN_NH; - if (ipc6.tclass < 0) - ipc6.tclass = np->tclass; - fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); @@ -933,9 +930,6 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (ipc6.hlimit < 0) ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); - if (ipc6.dontfrag < 0) - ipc6.dontfrag = np->dontfrag; - if (msg->msg_flags&MSG_CONFIRM) goto do_confirm; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index db9449b52dbe..de8382930910 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1313,7 +1313,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) int is_udplite = IS_UDPLITE(sk); int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); - ipcm6_init(&ipc6); + ipcm6_init_sk(&ipc6, np); ipc6.gso_size = READ_ONCE(up->gso_size); ipc6.sockc.tsflags = sk->sk_tsflags; ipc6.sockc.mark = sk->sk_mark; @@ -1518,9 +1518,6 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); - if (ipc6.tclass < 0) - ipc6.tclass = np->tclass; - fl6->flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6->flowlabel); dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p, connected); @@ -1566,8 +1563,6 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) up->pending = AF_INET6; do_append_data: - if (ipc6.dontfrag < 0) - ipc6.dontfrag = np->dontfrag; up->len += ulen; err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr), &ipc6, fl6, (struct rt6_info *)dst, diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index 217c7192691e..12406789bb28 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -521,7 +521,7 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) fl6.flowi6_mark = sk->sk_mark; fl6.flowi6_uid = sk->sk_uid; - ipcm6_init(&ipc6); + ipcm6_init_sk(&ipc6, np); if (lsa) { if (addr_len < SIN6_LEN_RFC2133) @@ -608,9 +608,6 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); - if (ipc6.tclass < 0) - ipc6.tclass = np->tclass; - fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); @@ -622,9 +619,6 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (ipc6.hlimit < 0) ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); - if (ipc6.dontfrag < 0) - ipc6.dontfrag = np->dontfrag; - if (msg->msg_flags & MSG_CONFIRM) goto do_confirm;
Users of ipcm6_init() have a somewhat complex post initialisation of ->dontfrag and ->tclass. Not only it adds additional overhead, but also complicates the code. First, replace ipcm6_init() with ipcm6_init_sk(). As it might be not an equivalent change, let's first look at ->dontfrag. The logic was to set it from cmsg if specified and otherwise fallback to np->dontfrag. Now it's initialising to np->dontfrag in the beginning and then potentially overriding with cmsg, which is absolutely the same behaviour. It's a bit more complex with ->tclass as ip6_datagram_send_ctl() might set it to -1, which is a default and not valid value. The solution here is to skip -1's specified in cmsg, so it'll be left with the socket default value getting us to the old behaviour. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- include/net/ipv6.h | 9 --------- net/ipv6/datagram.c | 4 ++-- net/ipv6/ip6_output.c | 2 -- net/ipv6/raw.c | 8 +------- net/ipv6/udp.c | 7 +------ net/l2tp/l2tp_ip6.c | 8 +------- 6 files changed, 5 insertions(+), 33 deletions(-)