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author | David S. Miller <davem@davemloft.net> | 2020-06-01 15:53:08 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2020-06-01 15:53:08 -0700 |
commit | 9a25c1df24a6fea9dc79eec950453c4e00f707fd (patch) | |
tree | 1188078f9838a3b6a60a3923ed31df142ffc8ed6 /net | |
parent | efd7ed0f5f2d07ccbb1853c5d46656cdfa1371fb (diff) | |
parent | cf51abcded837ef209faa03a62b2ea44e45995e8 (diff) | |
download | linux-stable-9a25c1df24a6fea9dc79eec950453c4e00f707fd.tar.gz linux-stable-9a25c1df24a6fea9dc79eec950453c4e00f707fd.tar.bz2 linux-stable-9a25c1df24a6fea9dc79eec950453c4e00f707fd.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-06-01
The following pull-request contains BPF updates for your *net-next* tree.
We've added 55 non-merge commits during the last 1 day(s) which contain
a total of 91 files changed, 4986 insertions(+), 463 deletions(-).
The main changes are:
1) Add rx_queue_mapping to bpf_sock from Amritha.
2) Add BPF ring buffer, from Andrii.
3) Attach and run programs through devmap, from David.
4) Allow SO_BINDTODEVICE opt in bpf_setsockopt, from Ferenc.
5) link based flow_dissector, from Jakub.
6) Use tracing helpers for lsm programs, from Jiri.
7) Several sk_msg fixes and extensions, from John.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/core/dev.c | 18 | ||||
-rw-r--r-- | net/core/filter.c | 94 | ||||
-rw-r--r-- | net/core/flow_dissector.c | 124 | ||||
-rw-r--r-- | net/core/skmsg.c | 98 | ||||
-rw-r--r-- | net/core/sock.c | 10 | ||||
-rw-r--r-- | net/ipv4/udp_tunnel.c | 2 | ||||
-rw-r--r-- | net/ipv6/ip6_udp_tunnel.c | 2 | ||||
-rw-r--r-- | net/tls/tls_sw.c | 20 |
8 files changed, 231 insertions, 137 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index ae37586f6ee8..10684833f864 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5420,6 +5420,18 @@ static int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp) struct bpf_prog *new = xdp->prog; int ret = 0; + if (new) { + u32 i; + + /* generic XDP does not work with DEVMAPs that can + * have a bpf_prog installed on an entry + */ + for (i = 0; i < new->aux->used_map_cnt; i++) { + if (dev_map_can_have_prog(new->aux->used_maps[i])) + return -EINVAL; + } + } + switch (xdp->command) { case XDP_SETUP_PROG: rcu_assign_pointer(dev->xdp_prog, new); @@ -8835,6 +8847,12 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, return -EINVAL; } + if (prog->expected_attach_type == BPF_XDP_DEVMAP) { + NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device"); + bpf_prog_put(prog); + return -EINVAL; + } + /* prog->aux->id may be 0 for orphaned device-bound progs */ if (prog->aux->id && prog->aux->id == prog_id) { bpf_prog_put(prog); diff --git a/net/core/filter.c b/net/core/filter.c index bd2853d23b50..ae82bcb03124 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4248,6 +4248,9 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = { static int _bpf_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen, u32 flags) { + char devname[IFNAMSIZ]; + struct net *net; + int ifindex; int ret = 0; int val; @@ -4257,7 +4260,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, sock_owned_by_me(sk); if (level == SOL_SOCKET) { - if (optlen != sizeof(int)) + if (optlen != sizeof(int) && optname != SO_BINDTODEVICE) return -EINVAL; val = *((int *)optval); @@ -4298,6 +4301,29 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, sk_dst_reset(sk); } break; + case SO_BINDTODEVICE: + ret = -ENOPROTOOPT; +#ifdef CONFIG_NETDEVICES + optlen = min_t(long, optlen, IFNAMSIZ - 1); + strncpy(devname, optval, optlen); + devname[optlen] = 0; + + ifindex = 0; + if (devname[0] != '\0') { + struct net_device *dev; + + ret = -ENODEV; + + net = sock_net(sk); + dev = dev_get_by_name(net, devname); + if (!dev) + break; + ifindex = dev->ifindex; + dev_put(dev); + } + ret = sock_bindtoindex(sk, ifindex, false); +#endif + break; default: ret = -EINVAL; } @@ -6443,6 +6469,26 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_msg_push_data_proto; case BPF_FUNC_msg_pop_data: return &bpf_msg_pop_data_proto; + case BPF_FUNC_perf_event_output: + return &bpf_event_output_data_proto; + case BPF_FUNC_get_current_uid_gid: + return &bpf_get_current_uid_gid_proto; + case BPF_FUNC_get_current_pid_tgid: + return &bpf_get_current_pid_tgid_proto; + case BPF_FUNC_sk_storage_get: + return &bpf_sk_storage_get_proto; + case BPF_FUNC_sk_storage_delete: + return &bpf_sk_storage_delete_proto; +#ifdef CONFIG_CGROUPS + case BPF_FUNC_get_current_cgroup_id: + return &bpf_get_current_cgroup_id_proto; + case BPF_FUNC_get_current_ancestor_cgroup_id: + return &bpf_get_current_ancestor_cgroup_id_proto; +#endif +#ifdef CONFIG_CGROUP_NET_CLASSID + case BPF_FUNC_get_cgroup_classid: + return &bpf_get_cgroup_classid_curr_proto; +#endif default: return bpf_base_func_proto(func_id); } @@ -6829,6 +6875,7 @@ bool bpf_sock_is_valid_access(int off, int size, enum bpf_access_type type, case offsetof(struct bpf_sock, protocol): case offsetof(struct bpf_sock, dst_port): case offsetof(struct bpf_sock, src_port): + case offsetof(struct bpf_sock, rx_queue_mapping): case bpf_ctx_range(struct bpf_sock, src_ip4): case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]): case bpf_ctx_range(struct bpf_sock, dst_ip4): @@ -6994,6 +7041,13 @@ static bool xdp_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { + if (prog->expected_attach_type != BPF_XDP_DEVMAP) { + switch (off) { + case offsetof(struct xdp_md, egress_ifindex): + return false; + } + } + if (type == BPF_WRITE) { if (bpf_prog_is_dev_bound(prog->aux)) { switch (off) { @@ -7257,6 +7311,11 @@ static bool sk_msg_is_valid_access(int off, int size, if (size != sizeof(__u64)) return false; break; + case offsetof(struct sk_msg_md, sk): + if (size != sizeof(__u64)) + return false; + info->reg_type = PTR_TO_SOCKET; + break; case bpf_ctx_range(struct sk_msg_md, family): case bpf_ctx_range(struct sk_msg_md, remote_ip4): case bpf_ctx_range(struct sk_msg_md, local_ip4): @@ -7872,6 +7931,23 @@ u32 bpf_sock_convert_ctx_access(enum bpf_access_type type, skc_state), target_size)); break; + case offsetof(struct bpf_sock, rx_queue_mapping): +#ifdef CONFIG_XPS + *insn++ = BPF_LDX_MEM( + BPF_FIELD_SIZEOF(struct sock, sk_rx_queue_mapping), + si->dst_reg, si->src_reg, + bpf_target_off(struct sock, sk_rx_queue_mapping, + sizeof_field(struct sock, + sk_rx_queue_mapping), + target_size)); + *insn++ = BPF_JMP_IMM(BPF_JNE, si->dst_reg, NO_QUEUE_MAPPING, + 1); + *insn++ = BPF_MOV64_IMM(si->dst_reg, -1); +#else + *insn++ = BPF_MOV64_IMM(si->dst_reg, -1); + *target_size = 2; +#endif + break; } return insn - insn_buf; @@ -7942,6 +8018,16 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, offsetof(struct xdp_rxq_info, queue_index)); break; + case offsetof(struct xdp_md, egress_ifindex): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_buff, txq), + si->dst_reg, si->src_reg, + offsetof(struct xdp_buff, txq)); + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_txq_info, dev), + si->dst_reg, si->dst_reg, + offsetof(struct xdp_txq_info, dev)); + *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg, + offsetof(struct net_device, ifindex)); + break; } return insn - insn_buf; @@ -8593,6 +8679,12 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type, si->dst_reg, si->src_reg, offsetof(struct sk_msg_sg, size)); break; + + case offsetof(struct sk_msg_md, sk): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_msg, sk), + si->dst_reg, si->src_reg, + offsetof(struct sk_msg, sk)); + break; } return insn - insn_buf; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 0aeb33572feb..d02df0b6d0d9 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -31,8 +31,7 @@ #include <net/netfilter/nf_conntrack_core.h> #include <net/netfilter/nf_conntrack_labels.h> #endif - -static DEFINE_MUTEX(flow_dissector_mutex); +#include <linux/bpf-netns.h> static void dissector_set_key(struct flow_dissector *flow_dissector, enum flow_dissector_key_id key_id) @@ -70,54 +69,11 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector, } EXPORT_SYMBOL(skb_flow_dissector_init); -int skb_flow_dissector_prog_query(const union bpf_attr *attr, - union bpf_attr __user *uattr) -{ - __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); - u32 prog_id, prog_cnt = 0, flags = 0; - struct bpf_prog *attached; - struct net *net; - - if (attr->query.query_flags) - return -EINVAL; - - net = get_net_ns_by_fd(attr->query.target_fd); - if (IS_ERR(net)) - return PTR_ERR(net); - - rcu_read_lock(); - attached = rcu_dereference(net->flow_dissector_prog); - if (attached) { - prog_cnt = 1; - prog_id = attached->aux->id; - } - rcu_read_unlock(); - - put_net(net); - - if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) - return -EFAULT; - if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt))) - return -EFAULT; - - if (!attr->query.prog_cnt || !prog_ids || !prog_cnt) - return 0; - - if (copy_to_user(prog_ids, &prog_id, sizeof(u32))) - return -EFAULT; - - return 0; -} - -int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, - struct bpf_prog *prog) +#ifdef CONFIG_BPF_SYSCALL +int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog) { + enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR; struct bpf_prog *attached; - struct net *net; - int ret = 0; - - net = current->nsproxy->net_ns; - mutex_lock(&flow_dissector_mutex); if (net == &init_net) { /* BPF flow dissector in the root namespace overrides @@ -130,70 +86,29 @@ int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, for_each_net(ns) { if (ns == &init_net) continue; - if (rcu_access_pointer(ns->flow_dissector_prog)) { - ret = -EEXIST; - goto out; - } + if (rcu_access_pointer(ns->bpf.progs[type])) + return -EEXIST; } } else { /* Make sure root flow dissector is not attached * when attaching to the non-root namespace. */ - if (rcu_access_pointer(init_net.flow_dissector_prog)) { - ret = -EEXIST; - goto out; - } + if (rcu_access_pointer(init_net.bpf.progs[type])) + return -EEXIST; } - attached = rcu_dereference_protected(net->flow_dissector_prog, - lockdep_is_held(&flow_dissector_mutex)); - if (attached == prog) { + attached = rcu_dereference_protected(net->bpf.progs[type], + lockdep_is_held(&netns_bpf_mutex)); + if (attached == prog) /* The same program cannot be attached twice */ - ret = -EINVAL; - goto out; - } - rcu_assign_pointer(net->flow_dissector_prog, prog); + return -EINVAL; + + rcu_assign_pointer(net->bpf.progs[type], prog); if (attached) bpf_prog_put(attached); -out: - mutex_unlock(&flow_dissector_mutex); - return ret; -} - -static int flow_dissector_bpf_prog_detach(struct net *net) -{ - struct bpf_prog *attached; - - mutex_lock(&flow_dissector_mutex); - attached = rcu_dereference_protected(net->flow_dissector_prog, - lockdep_is_held(&flow_dissector_mutex)); - if (!attached) { - mutex_unlock(&flow_dissector_mutex); - return -ENOENT; - } - RCU_INIT_POINTER(net->flow_dissector_prog, NULL); - bpf_prog_put(attached); - mutex_unlock(&flow_dissector_mutex); return 0; } - -int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) -{ - return flow_dissector_bpf_prog_detach(current->nsproxy->net_ns); -} - -static void __net_exit flow_dissector_pernet_pre_exit(struct net *net) -{ - /* We're not racing with attach/detach because there are no - * references to netns left when pre_exit gets called. - */ - if (rcu_access_pointer(net->flow_dissector_prog)) - flow_dissector_bpf_prog_detach(net); -} - -static struct pernet_operations flow_dissector_pernet_ops __net_initdata = { - .pre_exit = flow_dissector_pernet_pre_exit, -}; +#endif /* CONFIG_BPF_SYSCALL */ /** * __skb_flow_get_ports - extract the upper layer ports and return them @@ -1044,11 +959,13 @@ bool __skb_flow_dissect(const struct net *net, WARN_ON_ONCE(!net); if (net) { + enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR; + rcu_read_lock(); - attached = rcu_dereference(init_net.flow_dissector_prog); + attached = rcu_dereference(init_net.bpf.progs[type]); if (!attached) - attached = rcu_dereference(net->flow_dissector_prog); + attached = rcu_dereference(net->bpf.progs[type]); if (attached) { struct bpf_flow_keys flow_keys; @@ -1869,7 +1786,6 @@ static int __init init_default_flow_dissectors(void) skb_flow_dissector_init(&flow_keys_basic_dissector, flow_keys_basic_dissector_keys, ARRAY_SIZE(flow_keys_basic_dissector_keys)); - - return register_pernet_subsys(&flow_dissector_pernet_ops); + return 0; } core_initcall(init_default_flow_dissectors); diff --git a/net/core/skmsg.c b/net/core/skmsg.c index c479372f2cd2..351afbf6bfba 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -7,6 +7,7 @@ #include <net/sock.h> #include <net/tcp.h> +#include <net/tls.h> static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce) { @@ -682,13 +683,75 @@ static struct sk_psock *sk_psock_from_strp(struct strparser *strp) return container_of(parser, struct sk_psock, parser); } -static void sk_psock_verdict_apply(struct sk_psock *psock, - struct sk_buff *skb, int verdict) +static void sk_psock_skb_redirect(struct sk_psock *psock, struct sk_buff *skb) { struct sk_psock *psock_other; struct sock *sk_other; bool ingress; + sk_other = tcp_skb_bpf_redirect_fetch(skb); + if (unlikely(!sk_other)) { + kfree_skb(skb); + return; + } + psock_other = sk_psock(sk_other); + if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || + !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) { + kfree_skb(skb); + return; + } + + ingress = tcp_skb_bpf_ingress(skb); + if ((!ingress && sock_writeable(sk_other)) || + (ingress && + atomic_read(&sk_other->sk_rmem_alloc) <= + sk_other->sk_rcvbuf)) { + if (!ingress) + skb_set_owner_w(skb, sk_other); + skb_queue_tail(&psock_other->ingress_skb, skb); + schedule_work(&psock_other->work); + } else { + kfree_skb(skb); + } +} + +static void sk_psock_tls_verdict_apply(struct sk_psock *psock, + struct sk_buff *skb, int verdict) +{ + switch (verdict) { + case __SK_REDIRECT: + sk_psock_skb_redirect(psock, skb); + break; + case __SK_PASS: + case __SK_DROP: + default: + break; + } +} + +int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb) +{ + struct bpf_prog *prog; + int ret = __SK_PASS; + + rcu_read_lock(); + prog = READ_ONCE(psock->progs.skb_verdict); + if (likely(prog)) { + tcp_skb_bpf_redirect_clear(skb); + ret = sk_psock_bpf_run(psock, prog, skb); + ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); + } + rcu_read_unlock(); + sk_psock_tls_verdict_apply(psock, skb, ret); + return ret; +} +EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read); + +static void sk_psock_verdict_apply(struct sk_psock *psock, + struct sk_buff *skb, int verdict) +{ + struct sock *sk_other; + switch (verdict) { case __SK_PASS: sk_other = psock->sk; @@ -707,25 +770,8 @@ static void sk_psock_verdict_apply(struct sk_psock *psock, } goto out_free; case __SK_REDIRECT: - sk_other = tcp_skb_bpf_redirect_fetch(skb); - if (unlikely(!sk_other)) - goto out_free; - psock_other = sk_psock(sk_other); - if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || - !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) - goto out_free; - ingress = tcp_skb_bpf_ingress(skb); - if ((!ingress && sock_writeable(sk_other)) || - (ingress && - atomic_read(&sk_other->sk_rmem_alloc) <= - sk_other->sk_rcvbuf)) { - if (!ingress) - skb_set_owner_w(skb, sk_other); - skb_queue_tail(&psock_other->ingress_skb, skb); - schedule_work(&psock_other->work); - break; - } - /* fall-through */ + sk_psock_skb_redirect(psock, skb); + break; case __SK_DROP: /* fall-through */ default: @@ -779,9 +825,13 @@ static void sk_psock_strp_data_ready(struct sock *sk) rcu_read_lock(); psock = sk_psock(sk); if (likely(psock)) { - write_lock_bh(&sk->sk_callback_lock); - strp_data_ready(&psock->parser.strp); - write_unlock_bh(&sk->sk_callback_lock); + if (tls_sw_has_ctx_rx(sk)) { + psock->parser.saved_data_ready(sk); + } else { + write_lock_bh(&sk->sk_callback_lock); + strp_data_ready(&psock->parser.strp); + write_unlock_bh(&sk->sk_callback_lock); + } } rcu_read_unlock(); } diff --git a/net/core/sock.c b/net/core/sock.c index 61ec573221a6..6c4acf1f0220 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -594,13 +594,15 @@ out: return ret; } -int sock_bindtoindex(struct sock *sk, int ifindex) +int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk) { int ret; - lock_sock(sk); + if (lock_sk) + lock_sock(sk); ret = sock_bindtoindex_locked(sk, ifindex); - release_sock(sk); + if (lock_sk) + release_sock(sk); return ret; } @@ -646,7 +648,7 @@ static int sock_setbindtodevice(struct sock *sk, char __user *optval, goto out; } - return sock_bindtoindex(sk, index); + return sock_bindtoindex(sk, index, true); out: #endif diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c index 2158e8bddf41..3eecba0874aa 100644 --- a/net/ipv4/udp_tunnel.c +++ b/net/ipv4/udp_tunnel.c @@ -22,7 +22,7 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg, goto error; if (cfg->bind_ifindex) { - err = sock_bindtoindex(sock->sk, cfg->bind_ifindex); + err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true); if (err < 0) goto error; } diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c index 2e0ad1bc84a8..cdc4d4ee2420 100644 --- a/net/ipv6/ip6_udp_tunnel.c +++ b/net/ipv6/ip6_udp_tunnel.c @@ -30,7 +30,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg, goto error; } if (cfg->bind_ifindex) { - err = sock_bindtoindex(sock->sk, cfg->bind_ifindex); + err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true); if (err < 0) goto error; } diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 8c2763eb6aae..24f64bc0de18 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1742,6 +1742,7 @@ int tls_sw_recvmsg(struct sock *sk, long timeo; bool is_kvec = iov_iter_is_kvec(&msg->msg_iter); bool is_peek = flags & MSG_PEEK; + bool bpf_strp_enabled; int num_async = 0; int pending; @@ -1752,6 +1753,7 @@ int tls_sw_recvmsg(struct sock *sk, psock = sk_psock_get(sk); lock_sock(sk); + bpf_strp_enabled = sk_psock_strp_enabled(psock); /* Process pending decrypted records. It must be non-zero-copy */ err = process_rx_list(ctx, msg, &control, &cmsg, 0, len, false, @@ -1805,11 +1807,12 @@ int tls_sw_recvmsg(struct sock *sk, if (to_decrypt <= len && !is_kvec && !is_peek && ctx->control == TLS_RECORD_TYPE_DATA && - prot->version != TLS_1_3_VERSION) + prot->version != TLS_1_3_VERSION && + !bpf_strp_enabled) zc = true; /* Do not use async mode if record is non-data */ - if (ctx->control == TLS_RECORD_TYPE_DATA) + if (ctx->control == TLS_RECORD_TYPE_DATA && !bpf_strp_enabled) async_capable = ctx->async_capable; else async_capable = false; @@ -1859,6 +1862,19 @@ int tls_sw_recvmsg(struct sock *sk, goto pick_next_record; if (!zc) { + if (bpf_strp_enabled) { + err = sk_psock_tls_strp_read(psock, skb); + if (err != __SK_PASS) { + rxm->offset = rxm->offset + rxm->full_len; + rxm->full_len = 0; + if (err == __SK_DROP) + consume_skb(skb); + ctx->recv_pkt = NULL; + __strp_unpause(&ctx->strp); + continue; + } + } + if (rxm->full_len > len) { retain_skb = true; chunk = len; |