| Message ID | 20200414090925.GA10402@white |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v3] net: UDP repair mode for retrieving the send queue of corked UDP socket | expand |
Hi, I'm sorry for the late feedback, but I have a few comments... On Tue, 2020-04-14 at 12:09 +0300, Leşe Doru Călin wrote: > In this year's edition of GSoC, there is a project idea for CRIU to add > support for checkpoint/restore of cork-ed UDP sockets. But to add it, the > kernel API needs to be extended. > > This is what this patch does. It adds UDP "repair mode" for UDP sockets in > a similar approach to the TCP "repair mode", but only the send queue is > necessary to be retrieved. So the patch extends the recv and setsockopt > syscalls. Using UDP_REPAIR option in setsockopt, caller can set the socket > in repair mode. If it is setted, the recv/recvfrom/recvmsg will receive the > write queue and the destination of the data. As in the TCP mode, to change > the repair mode requires the CAP_NET_ADMIN capability and to receive data > the caller is obliged to use the MSG_PEEK flag. > > Signed-off-by: Lese Doru Calin <lesedorucalin01@gmail.com> > --- [...] @@ -1739,6 +1763,12 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > if (flags & MSG_ERRQUEUE) > return ip_recv_error(sk, msg, len, addr_len); > > + if (unlikely(up->repair)) { > + if (!peeking) > + return -EPERM; > + goto recv_sndq; > + } If the code deduplication suggested below applies, perhaps you can avoid the 'goto' statement and keep the 'repair' related code isolated in a single place. [...] > > cond_resched(); > msg->msg_flags &= ~MSG_TRUNC; > goto try_again; > + > +recv_sndq: > + off = sizeof(struct iphdr) + sizeof(struct udphdr); > + if (sin) { > + fl4 = &inet->cork.fl.u.ip4; > + sin->sin_family = AF_INET; > + sin->sin_port = fl4->fl4_dport; > + sin->sin_addr.s_addr = fl4->daddr; > + memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); > + *addr_len = sizeof(*sin); Here the BPF_CGROUP_UDP4_RECVMSG hook is not invoked, why? Perhaps you can reduce code duplication moving the esisting sin addr handling to an helper, taking addr and port as arguments, and re-using it here. [...] > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > index 7d4151747340..ec653f9fce2d 100644 > --- a/net/ipv6/udp.c > +++ b/net/ipv6/udp.c > @@ -250,6 +250,28 @@ struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be > EXPORT_SYMBOL_GPL(udp6_lib_lookup); > #endif > > +static int udp6_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > +{ > + int copy, copied = 0, err = 0; > + struct sk_buff *skb; > + > + skb_queue_walk(&sk->sk_write_queue, skb) { > + copy = len - copied; > + if (copy > skb->len - off) > + copy = skb->len - off; > + > + err = skb_copy_datagram_msg(skb, off, msg, copy); > + if (err) > + break; > + > + copied += copy; > + > + if (len <= copied) > + break; > + } > + return err ?: copied; > +} > + This looks identical to the v4 version to me. If so, you could re-use the same helper, exporting it. Cheers, Paolo
On 4/14/20 2:09 AM, Leşe Doru Călin wrote: > In this year's edition of GSoC, there is a project idea for CRIU to add > support for checkpoint/restore of cork-ed UDP sockets. But to add it, the > kernel API needs to be extended. > > This is what this patch does. It adds UDP "repair mode" for UDP sockets in > a similar approach to the TCP "repair mode", but only the send queue is > necessary to be retrieved. So the patch extends the recv and setsockopt > syscalls. Using UDP_REPAIR option in setsockopt, caller can set the socket > in repair mode. If it is setted, the recv/recvfrom/recvmsg will receive the > write queue and the destination of the data. As in the TCP mode, to change > the repair mode requires the CAP_NET_ADMIN capability and to receive data > the caller is obliged to use the MSG_PEEK flag. > > Signed-off-by: Lese Doru Calin <lesedorucalin01@gmail.com> > --- > include/linux/udp.h | 3 ++- > include/uapi/linux/udp.h | 1 + > net/ipv4/udp.c | 55 ++++++++++++++++++++++++++++++++++++++++ > net/ipv6/udp.c | 45 ++++++++++++++++++++++++++++++++ > 4 files changed, 103 insertions(+), 1 deletion(-) > > diff --git a/include/linux/udp.h b/include/linux/udp.h > index aa84597bdc33..b22bd70118ce 100644 > --- a/include/linux/udp.h > +++ b/include/linux/udp.h > @@ -51,7 +51,8 @@ struct udp_sock { > * different encapsulation layer set > * this > */ > - gro_enabled:1; /* Can accept GRO packets */ > + gro_enabled:1, /* Can accept GRO packets */ > + repair:1;/* Receive the send queue */ > /* > * Following member retains the information to create a UDP header > * when the socket is uncorked. > diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h > index 4828794efcf8..2fe78329d6da 100644 > --- a/include/uapi/linux/udp.h > +++ b/include/uapi/linux/udp.h > @@ -29,6 +29,7 @@ struct udphdr { > > /* UDP socket options */ > #define UDP_CORK 1 /* Never send partially complete segments */ > +#define UDP_REPAIR 19 /* Receive the send queue */ > #define UDP_ENCAP 100 /* Set the socket to accept encapsulated packets */ > #define UDP_NO_CHECK6_TX 101 /* Disable sending checksum for UDP6X */ > #define UDP_NO_CHECK6_RX 102 /* Disable accpeting checksum for UDP6 */ > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 32564b350823..dc9d15d564d6 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -1720,6 +1720,28 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, > } > EXPORT_SYMBOL(__skb_recv_udp); > > +static int udp_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > +{ > + int copy, copied = 0, err = 0; > + struct sk_buff *skb; > + > + skb_queue_walk(&sk->sk_write_queue, skb) { > + copy = len - copied; > + if (copy > skb->len - off) > + copy = skb->len - off; > + > + err = skb_copy_datagram_msg(skb, off, msg, copy); > + if (err) > + break; > + > + copied += copy; > + > + if (len <= copied) > + break; > + } > + return err ?: copied; > +} > + > /* > * This should be easy, if there is something there we > * return it, otherwise we block. > @@ -1729,8 +1751,10 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > int flags, int *addr_len) > { > struct inet_sock *inet = inet_sk(sk); > + struct udp_sock *up = udp_sk(sk); > DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); > struct sk_buff *skb; > + struct flowi4 *fl4; > unsigned int ulen, copied; > int off, err, peeking = flags & MSG_PEEK; > int is_udplite = IS_UDPLITE(sk); > @@ -1739,6 +1763,12 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > if (flags & MSG_ERRQUEUE) > return ip_recv_error(sk, msg, len, addr_len); > > + if (unlikely(up->repair)) { Socket lock is not held, disaster seems possible :/ > + if (!peeking) > + return -EPERM; > + goto recv_sndq; > + } > + Really, I would rather stop adding code in fast path for REPAIR stuff. A new setsockopt() would be much better I think. > try_again: > off = sk_peek_offset(sk, flags); > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > @@ -1832,6 +1862,18 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > cond_resched(); > msg->msg_flags &= ~MSG_TRUNC; > goto try_again; > + > +recv_sndq: > + off = sizeof(struct iphdr) + sizeof(struct udphdr); > + if (sin) { > + fl4 = &inet->cork.fl.u.ip4; > + sin->sin_family = AF_INET; > + sin->sin_port = fl4->fl4_dport; > + sin->sin_addr.s_addr = fl4->daddr; > + memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); > + *addr_len = sizeof(*sin); > + } > + return udp_peek_sndq(sk, msg, off, len); > } > > int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) > @@ -2557,6 +2599,15 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, > } > break; > > + case UDP_REPAIR: > + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) > + err = -EPERM; > + else if (val != 0) > + up->repair = 1; > + else > + up->repair = 0; > + break; > + > case UDP_ENCAP: > switch (val) { > case 0: > @@ -2678,6 +2729,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, > val = up->corkflag; > break; > > + case UDP_REPAIR: > + val = up->repair; > + break; > + > case UDP_ENCAP: > val = up->encap_type; > break; > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > index 7d4151747340..ec653f9fce2d 100644 > --- a/net/ipv6/udp.c > +++ b/net/ipv6/udp.c > @@ -250,6 +250,28 @@ struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be > EXPORT_SYMBOL_GPL(udp6_lib_lookup); > #endif > > +static int udp6_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > +{ > + int copy, copied = 0, err = 0; > + struct sk_buff *skb; > + > + skb_queue_walk(&sk->sk_write_queue, skb) { > + copy = len - copied; > + if (copy > skb->len - off) > + copy = skb->len - off; > + > + err = skb_copy_datagram_msg(skb, off, msg, copy); > + if (err) > + break; > + > + copied += copy; > + > + if (len <= copied) > + break; > + } > + return err ?: copied; > +} > + > /* do not use the scratch area len for jumbogram: their length execeeds the > * scratch area space; note that the IP6CB flags is still in the first > * cacheline, so checking for jumbograms is cheap > @@ -269,7 +291,9 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > { > struct ipv6_pinfo *np = inet6_sk(sk); > struct inet_sock *inet = inet_sk(sk); > + struct udp_sock *up = udp_sk(sk); > struct sk_buff *skb; > + struct flowi6 *fl6; > unsigned int ulen, copied; > int off, err, peeking = flags & MSG_PEEK; > int is_udplite = IS_UDPLITE(sk); > @@ -283,6 +307,12 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > if (np->rxpmtu && np->rxopt.bits.rxpmtu) > return ipv6_recv_rxpmtu(sk, msg, len, addr_len); > > + if (unlikely(up->repair)) { > + if (!peeking) > + return -EPERM; > + goto recv_sndq; > + } > + > try_again: > off = sk_peek_offset(sk, flags); > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > @@ -394,6 +424,21 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > cond_resched(); > msg->msg_flags &= ~MSG_TRUNC; > goto try_again; > + > +recv_sndq: > + off = sizeof(struct ipv6hdr) + sizeof(struct udphdr); > + if (msg->msg_name) { > + DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name); > + > + fl6 = &inet->cork.fl.u.ip6; > + sin6->sin6_family = AF_INET6; > + sin6->sin6_port = fl6->fl6_dport; > + sin6->sin6_flowinfo = 0; > + sin6->sin6_addr = fl6->daddr; > + sin6->sin6_scope_id = fl6->flowi6_oif; > + *addr_len = sizeof(*sin6); > + } > + return udp6_peek_sndq(sk, msg, off, len); > } > > DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key); >
On Tue, Apr 14, 2020 at 11:43:59AM -0700, Eric Dumazet wrote: > > > On 4/14/20 2:09 AM, Lese Doru Calin wrote: > > In this year's edition of GSoC, there is a project idea for CRIU to add > > support for checkpoint/restore of cork-ed UDP sockets. But to add it, the > > kernel API needs to be extended. > > > > This is what this patch does. It adds UDP "repair mode" for UDP sockets in > > a similar approach to the TCP "repair mode", but only the send queue is > > necessary to be retrieved. So the patch extends the recv and setsockopt > > syscalls. Using UDP_REPAIR option in setsockopt, caller can set the socket > > in repair mode. If it is setted, the recv/recvfrom/recvmsg will receive the > > write queue and the destination of the data. As in the TCP mode, to change > > the repair mode requires the CAP_NET_ADMIN capability and to receive data > > the caller is obliged to use the MSG_PEEK flag. > > > > Signed-off-by: Lese Doru Calin <lesedorucalin01@gmail.com> > > --- > > include/linux/udp.h | 3 ++- > > include/uapi/linux/udp.h | 1 + > > net/ipv4/udp.c | 55 ++++++++++++++++++++++++++++++++++++++++ > > net/ipv6/udp.c | 45 ++++++++++++++++++++++++++++++++ > > 4 files changed, 103 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/udp.h b/include/linux/udp.h > > index aa84597bdc33..b22bd70118ce 100644 > > --- a/include/linux/udp.h > > +++ b/include/linux/udp.h > > @@ -51,7 +51,8 @@ struct udp_sock { > > * different encapsulation layer set > > * this > > */ > > - gro_enabled:1; /* Can accept GRO packets */ > > + gro_enabled:1, /* Can accept GRO packets */ > > + repair:1;/* Receive the send queue */ > > /* > > * Following member retains the information to create a UDP header > > * when the socket is uncorked. > > diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h > > index 4828794efcf8..2fe78329d6da 100644 > > --- a/include/uapi/linux/udp.h > > +++ b/include/uapi/linux/udp.h > > @@ -29,6 +29,7 @@ struct udphdr { > > > > /* UDP socket options */ > > #define UDP_CORK 1 /* Never send partially complete segments */ > > +#define UDP_REPAIR 19 /* Receive the send queue */ > > #define UDP_ENCAP 100 /* Set the socket to accept encapsulated packets */ > > #define UDP_NO_CHECK6_TX 101 /* Disable sending checksum for UDP6X */ > > #define UDP_NO_CHECK6_RX 102 /* Disable accpeting checksum for UDP6 */ > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > > index 32564b350823..dc9d15d564d6 100644 > > --- a/net/ipv4/udp.c > > +++ b/net/ipv4/udp.c > > @@ -1720,6 +1720,28 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, > > } > > EXPORT_SYMBOL(__skb_recv_udp); > > > > +static int udp_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > > +{ > > + int copy, copied = 0, err = 0; > > + struct sk_buff *skb; > > + > > + skb_queue_walk(&sk->sk_write_queue, skb) { > > + copy = len - copied; > > + if (copy > skb->len - off) > > + copy = skb->len - off; > > + > > + err = skb_copy_datagram_msg(skb, off, msg, copy); > > + if (err) > > + break; > > + > > + copied += copy; > > + > > + if (len <= copied) > > + break; > > + } > > + return err ?: copied; > > +} > > + > > /* > > * This should be easy, if there is something there we > > * return it, otherwise we block. > > @@ -1729,8 +1751,10 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > int flags, int *addr_len) > > { > > struct inet_sock *inet = inet_sk(sk); > > + struct udp_sock *up = udp_sk(sk); > > DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); > > struct sk_buff *skb; > > + struct flowi4 *fl4; > > unsigned int ulen, copied; > > int off, err, peeking = flags & MSG_PEEK; > > int is_udplite = IS_UDPLITE(sk); > > @@ -1739,6 +1763,12 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > if (flags & MSG_ERRQUEUE) > > return ip_recv_error(sk, msg, len, addr_len); > > > > + if (unlikely(up->repair)) { > > Socket lock is not held, disaster seems possible :/ > I missed that. Sorry. > > + if (!peeking) > > + return -EPERM; > > + goto recv_sndq; > > + } > > + > > > Really, I would rather stop adding code in fast path for REPAIR stuff. > > A new setsockopt() would be much better I think. > I could implement it as a option for getsockopt syscall, with a pointer to a buffer or a user_msghdr as a parameter, so that other syscalls are not affected. > > try_again: > > off = sk_peek_offset(sk, flags); > > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > > @@ -1832,6 +1862,18 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > cond_resched(); > > msg->msg_flags &= ~MSG_TRUNC; > > goto try_again; > > + > > +recv_sndq: > > + off = sizeof(struct iphdr) + sizeof(struct udphdr); > > + if (sin) { > > + fl4 = &inet->cork.fl.u.ip4; > > + sin->sin_family = AF_INET; > > + sin->sin_port = fl4->fl4_dport; > > + sin->sin_addr.s_addr = fl4->daddr; > > + memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); > > + *addr_len = sizeof(*sin); > > + } > > + return udp_peek_sndq(sk, msg, off, len); > > } > > > > int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) > > @@ -2557,6 +2599,15 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, > > } > > break; > > > > + case UDP_REPAIR: > > + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) > > + err = -EPERM; > > + else if (val != 0) > > + up->repair = 1; > > + else > > + up->repair = 0; > > + break; > > + > > case UDP_ENCAP: > > switch (val) { > > case 0: > > @@ -2678,6 +2729,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, > > val = up->corkflag; > > break; > > > > + case UDP_REPAIR: > > + val = up->repair; > > + break; > > + > > case UDP_ENCAP: > > val = up->encap_type; > > break; > > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > > index 7d4151747340..ec653f9fce2d 100644 > > --- a/net/ipv6/udp.c > > +++ b/net/ipv6/udp.c > > @@ -250,6 +250,28 @@ struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be > > EXPORT_SYMBOL_GPL(udp6_lib_lookup); > > #endif > > > > +static int udp6_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > > +{ > > + int copy, copied = 0, err = 0; > > + struct sk_buff *skb; > > + > > + skb_queue_walk(&sk->sk_write_queue, skb) { > > + copy = len - copied; > > + if (copy > skb->len - off) > > + copy = skb->len - off; > > + > > + err = skb_copy_datagram_msg(skb, off, msg, copy); > > + if (err) > > + break; > > + > > + copied += copy; > > + > > + if (len <= copied) > > + break; > > + } > > + return err ?: copied; > > +} > > + > > /* do not use the scratch area len for jumbogram: their length execeeds the > > * scratch area space; note that the IP6CB flags is still in the first > > * cacheline, so checking for jumbograms is cheap > > @@ -269,7 +291,9 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > { > > struct ipv6_pinfo *np = inet6_sk(sk); > > struct inet_sock *inet = inet_sk(sk); > > + struct udp_sock *up = udp_sk(sk); > > struct sk_buff *skb; > > + struct flowi6 *fl6; > > unsigned int ulen, copied; > > int off, err, peeking = flags & MSG_PEEK; > > int is_udplite = IS_UDPLITE(sk); > > @@ -283,6 +307,12 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > if (np->rxpmtu && np->rxopt.bits.rxpmtu) > > return ipv6_recv_rxpmtu(sk, msg, len, addr_len); > > > > + if (unlikely(up->repair)) { > > + if (!peeking) > > + return -EPERM; > > + goto recv_sndq; > > + } > > + > > try_again: > > off = sk_peek_offset(sk, flags); > > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > > @@ -394,6 +424,21 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > cond_resched(); > > msg->msg_flags &= ~MSG_TRUNC; > > goto try_again; > > + > > +recv_sndq: > > + off = sizeof(struct ipv6hdr) + sizeof(struct udphdr); > > + if (msg->msg_name) { > > + DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name); > > + > > + fl6 = &inet->cork.fl.u.ip6; > > + sin6->sin6_family = AF_INET6; > > + sin6->sin6_port = fl6->fl6_dport; > > + sin6->sin6_flowinfo = 0; > > + sin6->sin6_addr = fl6->daddr; > > + sin6->sin6_scope_id = fl6->flowi6_oif; > > + *addr_len = sizeof(*sin6); > > + } > > + return udp6_peek_sndq(sk, msg, off, len); > > } > > > > DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key); > >
diff --git a/include/linux/udp.h b/include/linux/udp.h index aa84597bdc33..b22bd70118ce 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -51,7 +51,8 @@ struct udp_sock { * different encapsulation layer set * this */ - gro_enabled:1; /* Can accept GRO packets */ + gro_enabled:1, /* Can accept GRO packets */ + repair:1;/* Receive the send queue */ /* * Following member retains the information to create a UDP header * when the socket is uncorked. diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h index 4828794efcf8..2fe78329d6da 100644 --- a/include/uapi/linux/udp.h +++ b/include/uapi/linux/udp.h @@ -29,6 +29,7 @@ struct udphdr { /* UDP socket options */ #define UDP_CORK 1 /* Never send partially complete segments */ +#define UDP_REPAIR 19 /* Receive the send queue */ #define UDP_ENCAP 100 /* Set the socket to accept encapsulated packets */ #define UDP_NO_CHECK6_TX 101 /* Disable sending checksum for UDP6X */ #define UDP_NO_CHECK6_RX 102 /* Disable accpeting checksum for UDP6 */ diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 32564b350823..dc9d15d564d6 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1720,6 +1720,28 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, } EXPORT_SYMBOL(__skb_recv_udp); +static int udp_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) +{ + int copy, copied = 0, err = 0; + struct sk_buff *skb; + + skb_queue_walk(&sk->sk_write_queue, skb) { + copy = len - copied; + if (copy > skb->len - off) + copy = skb->len - off; + + err = skb_copy_datagram_msg(skb, off, msg, copy); + if (err) + break; + + copied += copy; + + if (len <= copied) + break; + } + return err ?: copied; +} + /* * This should be easy, if there is something there we * return it, otherwise we block. @@ -1729,8 +1751,10 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, int flags, int *addr_len) { struct inet_sock *inet = inet_sk(sk); + struct udp_sock *up = udp_sk(sk); DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); struct sk_buff *skb; + struct flowi4 *fl4; unsigned int ulen, copied; int off, err, peeking = flags & MSG_PEEK; int is_udplite = IS_UDPLITE(sk); @@ -1739,6 +1763,12 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, if (flags & MSG_ERRQUEUE) return ip_recv_error(sk, msg, len, addr_len); + if (unlikely(up->repair)) { + if (!peeking) + return -EPERM; + goto recv_sndq; + } + try_again: off = sk_peek_offset(sk, flags); skb = __skb_recv_udp(sk, flags, noblock, &off, &err); @@ -1832,6 +1862,18 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, cond_resched(); msg->msg_flags &= ~MSG_TRUNC; goto try_again; + +recv_sndq: + off = sizeof(struct iphdr) + sizeof(struct udphdr); + if (sin) { + fl4 = &inet->cork.fl.u.ip4; + sin->sin_family = AF_INET; + sin->sin_port = fl4->fl4_dport; + sin->sin_addr.s_addr = fl4->daddr; + memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); + *addr_len = sizeof(*sin); + } + return udp_peek_sndq(sk, msg, off, len); } int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) @@ -2557,6 +2599,15 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, } break; + case UDP_REPAIR: + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) + err = -EPERM; + else if (val != 0) + up->repair = 1; + else + up->repair = 0; + break; + case UDP_ENCAP: switch (val) { case 0: @@ -2678,6 +2729,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, val = up->corkflag; break; + case UDP_REPAIR: + val = up->repair; + break; + case UDP_ENCAP: val = up->encap_type; break; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 7d4151747340..ec653f9fce2d 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -250,6 +250,28 @@ struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be EXPORT_SYMBOL_GPL(udp6_lib_lookup); #endif +static int udp6_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) +{ + int copy, copied = 0, err = 0; + struct sk_buff *skb; + + skb_queue_walk(&sk->sk_write_queue, skb) { + copy = len - copied; + if (copy > skb->len - off) + copy = skb->len - off; + + err = skb_copy_datagram_msg(skb, off, msg, copy); + if (err) + break; + + copied += copy; + + if (len <= copied) + break; + } + return err ?: copied; +} + /* do not use the scratch area len for jumbogram: their length execeeds the * scratch area space; note that the IP6CB flags is still in the first * cacheline, so checking for jumbograms is cheap @@ -269,7 +291,9 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, { struct ipv6_pinfo *np = inet6_sk(sk); struct inet_sock *inet = inet_sk(sk); + struct udp_sock *up = udp_sk(sk); struct sk_buff *skb; + struct flowi6 *fl6; unsigned int ulen, copied; int off, err, peeking = flags & MSG_PEEK; int is_udplite = IS_UDPLITE(sk); @@ -283,6 +307,12 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, if (np->rxpmtu && np->rxopt.bits.rxpmtu) return ipv6_recv_rxpmtu(sk, msg, len, addr_len); + if (unlikely(up->repair)) { + if (!peeking) + return -EPERM; + goto recv_sndq; + } + try_again: off = sk_peek_offset(sk, flags); skb = __skb_recv_udp(sk, flags, noblock, &off, &err); @@ -394,6 +424,21 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, cond_resched(); msg->msg_flags &= ~MSG_TRUNC; goto try_again; + +recv_sndq: + off = sizeof(struct ipv6hdr) + sizeof(struct udphdr); + if (msg->msg_name) { + DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name); + + fl6 = &inet->cork.fl.u.ip6; + sin6->sin6_family = AF_INET6; + sin6->sin6_port = fl6->fl6_dport; + sin6->sin6_flowinfo = 0; + sin6->sin6_addr = fl6->daddr; + sin6->sin6_scope_id = fl6->flowi6_oif; + *addr_len = sizeof(*sin6); + } + return udp6_peek_sndq(sk, msg, off, len); } DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
In this year's edition of GSoC, there is a project idea for CRIU to add support for checkpoint/restore of cork-ed UDP sockets. But to add it, the kernel API needs to be extended. This is what this patch does. It adds UDP "repair mode" for UDP sockets in a similar approach to the TCP "repair mode", but only the send queue is necessary to be retrieved. So the patch extends the recv and setsockopt syscalls. Using UDP_REPAIR option in setsockopt, caller can set the socket in repair mode. If it is setted, the recv/recvfrom/recvmsg will receive the write queue and the destination of the data. As in the TCP mode, to change the repair mode requires the CAP_NET_ADMIN capability and to receive data the caller is obliged to use the MSG_PEEK flag. Signed-off-by: Lese Doru Calin <lesedorucalin01@gmail.com> --- include/linux/udp.h | 3 ++- include/uapi/linux/udp.h | 1 + net/ipv4/udp.c | 55 ++++++++++++++++++++++++++++++++++++++++ net/ipv6/udp.c | 45 ++++++++++++++++++++++++++++++++ 4 files changed, 103 insertions(+), 1 deletion(-)