diff options
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/Makefile | 2 | ||||
| -rw-r--r-- | net/core/filter.c | 121 | ||||
| -rw-r--r-- | net/core/sock.c | 29 | ||||
| -rw-r--r-- | net/core/sock_reuseport.c | 251 |
4 files changed, 380 insertions, 23 deletions
diff --git a/net/core/Makefile b/net/core/Makefile index 086b01fbe1bd..0b835de04de3 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -9,7 +9,7 @@ obj-$(CONFIG_SYSCTL) += sysctl_net_core.o obj-y += dev.o ethtool.o dev_addr_lists.o dst.o netevent.o \ neighbour.o rtnetlink.o utils.o link_watch.o filter.o \ - sock_diag.o dev_ioctl.o tso.o + sock_diag.o dev_ioctl.o tso.o sock_reuseport.o obj-$(CONFIG_XFRM) += flow.o obj-y += net-sysfs.o diff --git a/net/core/filter.c b/net/core/filter.c index c770196ae8d5..35e6fed28709 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -50,6 +50,7 @@ #include <net/cls_cgroup.h> #include <net/dst_metadata.h> #include <net/dst.h> +#include <net/sock_reuseport.h> /** * sk_filter - run a packet through a socket filter @@ -1167,17 +1168,32 @@ static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk) return 0; } -/** - * sk_attach_filter - attach a socket filter - * @fprog: the filter program - * @sk: the socket to use - * - * Attach the user's filter code. We first run some sanity checks on - * it to make sure it does not explode on us later. If an error - * occurs or there is insufficient memory for the filter a negative - * errno code is returned. On success the return is zero. - */ -int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) +static int __reuseport_attach_prog(struct bpf_prog *prog, struct sock *sk) +{ + struct bpf_prog *old_prog; + int err; + + if (bpf_prog_size(prog->len) > sysctl_optmem_max) + return -ENOMEM; + + if (sk_unhashed(sk)) { + err = reuseport_alloc(sk); + if (err) + return err; + } else if (!rcu_access_pointer(sk->sk_reuseport_cb)) { + /* The socket wasn't bound with SO_REUSEPORT */ + return -EINVAL; + } + + old_prog = reuseport_attach_prog(sk, prog); + if (old_prog) + bpf_prog_destroy(old_prog); + + return 0; +} + +static +struct bpf_prog *__get_filter(struct sock_fprog *fprog, struct sock *sk) { unsigned int fsize = bpf_classic_proglen(fprog); unsigned int bpf_fsize = bpf_prog_size(fprog->len); @@ -1185,19 +1201,19 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) int err; if (sock_flag(sk, SOCK_FILTER_LOCKED)) - return -EPERM; + return ERR_PTR(-EPERM); /* Make sure new filter is there and in the right amounts. */ if (fprog->filter == NULL) - return -EINVAL; + return ERR_PTR(-EINVAL); prog = bpf_prog_alloc(bpf_fsize, 0); if (!prog) - return -ENOMEM; + return ERR_PTR(-ENOMEM); if (copy_from_user(prog->insns, fprog->filter, fsize)) { __bpf_prog_free(prog); - return -EFAULT; + return ERR_PTR(-EFAULT); } prog->len = fprog->len; @@ -1205,13 +1221,30 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) err = bpf_prog_store_orig_filter(prog, fprog); if (err) { __bpf_prog_free(prog); - return -ENOMEM; + return ERR_PTR(-ENOMEM); } /* bpf_prepare_filter() already takes care of freeing * memory in case something goes wrong. */ - prog = bpf_prepare_filter(prog, NULL); + return bpf_prepare_filter(prog, NULL); +} + +/** + * sk_attach_filter - attach a socket filter + * @fprog: the filter program + * @sk: the socket to use + * + * Attach the user's filter code. We first run some sanity checks on + * it to make sure it does not explode on us later. If an error + * occurs or there is insufficient memory for the filter a negative + * errno code is returned. On success the return is zero. + */ +int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) +{ + struct bpf_prog *prog = __get_filter(fprog, sk); + int err; + if (IS_ERR(prog)) return PTR_ERR(prog); @@ -1225,23 +1258,50 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) } EXPORT_SYMBOL_GPL(sk_attach_filter); -int sk_attach_bpf(u32 ufd, struct sock *sk) +int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk) { - struct bpf_prog *prog; + struct bpf_prog *prog = __get_filter(fprog, sk); int err; + if (IS_ERR(prog)) + return PTR_ERR(prog); + + err = __reuseport_attach_prog(prog, sk); + if (err < 0) { + __bpf_prog_release(prog); + return err; + } + + return 0; +} + +static struct bpf_prog *__get_bpf(u32 ufd, struct sock *sk) +{ + struct bpf_prog *prog; + if (sock_flag(sk, SOCK_FILTER_LOCKED)) - return -EPERM; + return ERR_PTR(-EPERM); prog = bpf_prog_get(ufd); if (IS_ERR(prog)) - return PTR_ERR(prog); + return prog; if (prog->type != BPF_PROG_TYPE_SOCKET_FILTER) { bpf_prog_put(prog); - return -EINVAL; + return ERR_PTR(-EINVAL); } + return prog; +} + +int sk_attach_bpf(u32 ufd, struct sock *sk) +{ + struct bpf_prog *prog = __get_bpf(ufd, sk); + int err; + + if (IS_ERR(prog)) + return PTR_ERR(prog); + err = __sk_attach_prog(prog, sk); if (err < 0) { bpf_prog_put(prog); @@ -1251,6 +1311,23 @@ int sk_attach_bpf(u32 ufd, struct sock *sk) return 0; } +int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk) +{ + struct bpf_prog *prog = __get_bpf(ufd, sk); + int err; + + if (IS_ERR(prog)) + return PTR_ERR(prog); + + err = __reuseport_attach_prog(prog, sk); + if (err < 0) { + bpf_prog_put(prog); + return err; + } + + return 0; +} + #define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1) #define BPF_LDST_LEN 16U diff --git a/net/core/sock.c b/net/core/sock.c index 565bab7baca9..51270238e269 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -134,6 +134,7 @@ #include <linux/sock_diag.h> #include <linux/filter.h> +#include <net/sock_reuseport.h> #include <trace/events/sock.h> @@ -932,6 +933,32 @@ set_rcvbuf: } break; + case SO_ATTACH_REUSEPORT_CBPF: + ret = -EINVAL; + if (optlen == sizeof(struct sock_fprog)) { + struct sock_fprog fprog; + + ret = -EFAULT; + if (copy_from_user(&fprog, optval, sizeof(fprog))) + break; + + ret = sk_reuseport_attach_filter(&fprog, sk); + } + break; + + case SO_ATTACH_REUSEPORT_EBPF: + ret = -EINVAL; + if (optlen == sizeof(u32)) { + u32 ufd; + + ret = -EFAULT; + if (copy_from_user(&ufd, optval, sizeof(ufd))) + break; + + ret = sk_reuseport_attach_bpf(ufd, sk); + } + break; + case SO_DETACH_FILTER: ret = sk_detach_filter(sk); break; @@ -1443,6 +1470,8 @@ void sk_destruct(struct sock *sk) sk_filter_uncharge(sk, filter); RCU_INIT_POINTER(sk->sk_filter, NULL); } + if (rcu_access_pointer(sk->sk_reuseport_cb)) + reuseport_detach_sock(sk); sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP); diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c new file mode 100644 index 000000000000..ae0969c0fc2e --- /dev/null +++ b/net/core/sock_reuseport.c @@ -0,0 +1,251 @@ +/* + * To speed up listener socket lookup, create an array to store all sockets + * listening on the same port. This allows a decision to be made after finding + * the first socket. An optional BPF program can also be configured for + * selecting the socket index from the array of available sockets. + */ + +#include <net/sock_reuseport.h> +#include <linux/bpf.h> +#include <linux/rcupdate.h> + +#define INIT_SOCKS 128 + +static DEFINE_SPINLOCK(reuseport_lock); + +static struct sock_reuseport *__reuseport_alloc(u16 max_socks) +{ + size_t size = sizeof(struct sock_reuseport) + + sizeof(struct sock *) * max_socks; + struct sock_reuseport *reuse = kzalloc(size, GFP_ATOMIC); + + if (!reuse) + return NULL; + + reuse->max_socks = max_socks; + + RCU_INIT_POINTER(reuse->prog, NULL); + return reuse; +} + +int reuseport_alloc(struct sock *sk) +{ + struct sock_reuseport *reuse; + + /* bh lock used since this function call may precede hlist lock in + * soft irq of receive path or setsockopt from process context + */ + spin_lock_bh(&reuseport_lock); + WARN_ONCE(rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + "multiple allocations for the same socket"); + reuse = __reuseport_alloc(INIT_SOCKS); + if (!reuse) { + spin_unlock_bh(&reuseport_lock); + return -ENOMEM; + } + + reuse->socks[0] = sk; + reuse->num_socks = 1; + rcu_assign_pointer(sk->sk_reuseport_cb, reuse); + + spin_unlock_bh(&reuseport_lock); + + return 0; +} +EXPORT_SYMBOL(reuseport_alloc); + +static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse) +{ + struct sock_reuseport *more_reuse; + u32 more_socks_size, i; + + more_socks_size = reuse->max_socks * 2U; + if (more_socks_size > U16_MAX) + return NULL; + + more_reuse = __reuseport_alloc(more_socks_size); + if (!more_reuse) + return NULL; + + more_reuse->max_socks = more_socks_size; + more_reuse->num_socks = reuse->num_socks; + more_reuse->prog = reuse->prog; + + memcpy(more_reuse->socks, reuse->socks, + reuse->num_socks * sizeof(struct sock *)); + + for (i = 0; i < reuse->num_socks; ++i) + rcu_assign_pointer(reuse->socks[i]->sk_reuseport_cb, + more_reuse); + + /* Note: we use kfree_rcu here instead of reuseport_free_rcu so + * that reuse and more_reuse can temporarily share a reference + * to prog. + */ + kfree_rcu(reuse, rcu); + return more_reuse; +} + +/** + * reuseport_add_sock - Add a socket to the reuseport group of another. + * @sk: New socket to add to the group. + * @sk2: Socket belonging to the existing reuseport group. + * May return ENOMEM and not add socket to group under memory pressure. + */ +int reuseport_add_sock(struct sock *sk, const struct sock *sk2) +{ + struct sock_reuseport *reuse; + + spin_lock_bh(&reuseport_lock); + reuse = rcu_dereference_protected(sk2->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + WARN_ONCE(rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + "socket already in reuseport group"); + + if (reuse->num_socks == reuse->max_socks) { + reuse = reuseport_grow(reuse); + if (!reuse) { + spin_unlock_bh(&reuseport_lock); + return -ENOMEM; + } + } + + reuse->socks[reuse->num_socks] = sk; + /* paired with smp_rmb() in reuseport_select_sock() */ + smp_wmb(); + reuse->num_socks++; + rcu_assign_pointer(sk->sk_reuseport_cb, reuse); + + spin_unlock_bh(&reuseport_lock); + + return 0; +} +EXPORT_SYMBOL(reuseport_add_sock); + +static void reuseport_free_rcu(struct rcu_head *head) +{ + struct sock_reuseport *reuse; + + reuse = container_of(head, struct sock_reuseport, rcu); + if (reuse->prog) + bpf_prog_destroy(reuse->prog); + kfree(reuse); +} + +void reuseport_detach_sock(struct sock *sk) +{ + struct sock_reuseport *reuse; + int i; + + spin_lock_bh(&reuseport_lock); + reuse = rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)); + rcu_assign_pointer(sk->sk_reuseport_cb, NULL); + + for (i = 0; i < reuse->num_socks; i++) { + if (reuse->socks[i] == sk) { + reuse->socks[i] = reuse->socks[reuse->num_socks - 1]; + reuse->num_socks--; + if (reuse->num_socks == 0) + call_rcu(&reuse->rcu, reuseport_free_rcu); + break; + } + } + spin_unlock_bh(&reuseport_lock); +} +EXPORT_SYMBOL(reuseport_detach_sock); + +static struct sock *run_bpf(struct sock_reuseport *reuse, u16 socks, + struct bpf_prog *prog, struct sk_buff *skb, + int hdr_len) +{ + struct sk_buff *nskb = NULL; + u32 index; + + if (skb_shared(skb)) { + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return NULL; + skb = nskb; + } + + /* temporarily advance data past protocol header */ + if (!pskb_pull(skb, hdr_len)) { + consume_skb(nskb); + return NULL; + } + index = bpf_prog_run_save_cb(prog, skb); + __skb_push(skb, hdr_len); + + consume_skb(nskb); + + if (index >= socks) + return NULL; + + return reuse->socks[index]; +} + +/** + * reuseport_select_sock - Select a socket from an SO_REUSEPORT group. + * @sk: First socket in the group. + * @hash: When no BPF filter is available, use this hash to select. + * @skb: skb to run through BPF filter. + * @hdr_len: BPF filter expects skb data pointer at payload data. If + * the skb does not yet point at the payload, this parameter represents + * how far the pointer needs to advance to reach the payload. + * Returns a socket that should receive the packet (or NULL on error). + */ +struct sock *reuseport_select_sock(struct sock *sk, + u32 hash, + struct sk_buff *skb, + int hdr_len) +{ + struct sock_reuseport *reuse; + struct bpf_prog *prog; + struct sock *sk2 = NULL; + u16 socks; + + rcu_read_lock(); + reuse = rcu_dereference(sk->sk_reuseport_cb); + + /* if memory allocation failed or add call is not yet complete */ + if (!reuse) + goto out; + + prog = rcu_dereference(reuse->prog); + socks = READ_ONCE(reuse->num_socks); + if (likely(socks)) { + /* paired with smp_wmb() in reuseport_add_sock() */ + smp_rmb(); + + if (prog && skb) + sk2 = run_bpf(reuse, socks, prog, skb, hdr_len); + else + sk2 = reuse->socks[reciprocal_scale(hash, socks)]; + } + +out: + rcu_read_unlock(); + return sk2; +} +EXPORT_SYMBOL(reuseport_select_sock); + +struct bpf_prog * +reuseport_attach_prog(struct sock *sk, struct bpf_prog *prog) +{ + struct sock_reuseport *reuse; + struct bpf_prog *old_prog; + + spin_lock_bh(&reuseport_lock); + reuse = rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)); + old_prog = rcu_dereference_protected(reuse->prog, + lockdep_is_held(&reuseport_lock)); + rcu_assign_pointer(reuse->prog, prog); + spin_unlock_bh(&reuseport_lock); + + return old_prog; +} +EXPORT_SYMBOL(reuseport_attach_prog); |