cregit-Linux how code gets into the kernel

Release 4.8 net/phonet/pep.c

Directory: net/phonet
/*
 * File: pep.c
 *
 * Phonet pipe protocol end point socket
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Author: Rémi Denis-Courmont
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <asm/ioctls.h>

#include <linux/phonet.h>
#include <linux/module.h>
#include <net/phonet/phonet.h>
#include <net/phonet/pep.h>
#include <net/phonet/gprs.h>

/* sk_state values:
 * TCP_CLOSE            sock not in use yet
 * TCP_CLOSE_WAIT       disconnected pipe
 * TCP_LISTEN           listening pipe endpoint
 * TCP_SYN_RECV         connected pipe in disabled state
 * TCP_ESTABLISHED      connected pipe in enabled state
 *
 * pep_sock locking:
 *  - sk_state, hlist: sock lock needed
 *  - listener: read only
 *  - pipe_handle: read only
 */


#define CREDITS_MAX	10

#define CREDITS_THR	7


#define pep_sb_size(s) (((s) + 5) & ~3) 
/* 2-bytes head, 32-bits aligned */

/* Get the next TLV sub-block. */

static unsigned char *pep_get_sb(struct sk_buff *skb, u8 *ptype, u8 *plen, void *buf) { void *data = NULL; struct { u8 sb_type; u8 sb_len; } *ph, h; int buflen = *plen; ph = skb_header_pointer(skb, 0, 2, &h); if (ph == NULL || ph->sb_len < 2 || !pskb_may_pull(skb, ph->sb_len)) return NULL; ph->sb_len -= 2; *ptype = ph->sb_type; *plen = ph->sb_len; if (buflen > ph->sb_len) buflen = ph->sb_len; data = skb_header_pointer(skb, 2, buflen, buf); __skb_pull(skb, 2 + ph->sb_len); return data; }

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static struct sk_buff *pep_alloc_skb(struct sock *sk, const void *payload, int len, gfp_t priority) { struct sk_buff *skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority); if (!skb) return NULL; skb_set_owner_w(skb, sk); skb_reserve(skb, MAX_PNPIPE_HEADER); __skb_put(skb, len); skb_copy_to_linear_data(skb, payload, len); __skb_push(skb, sizeof(struct pnpipehdr)); skb_reset_transport_header(skb); return skb; }

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static int pep_reply(struct sock *sk, struct sk_buff *oskb, u8 code, const void *data, int len, gfp_t priority) { const struct pnpipehdr *oph = pnp_hdr(oskb); struct pnpipehdr *ph; struct sk_buff *skb; struct sockaddr_pn peer; skb = pep_alloc_skb(sk, data, len, priority); if (!skb) return -ENOMEM; ph = pnp_hdr(skb); ph->utid = oph->utid; ph->message_id = oph->message_id + 1; /* REQ -> RESP */ ph->pipe_handle = oph->pipe_handle; ph->error_code = code; pn_skb_get_src_sockaddr(oskb, &peer); return pn_skb_send(sk, skb, &peer); }

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static int pep_indicate(struct sock *sk, u8 id, u8 code, const void *data, int len, gfp_t priority) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *ph; struct sk_buff *skb; skb = pep_alloc_skb(sk, data, len, priority); if (!skb) return -ENOMEM; ph = pnp_hdr(skb); ph->utid = 0; ph->message_id = id; ph->pipe_handle = pn->pipe_handle; ph->data[0] = code; return pn_skb_send(sk, skb, NULL); }

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#define PAD 0x00
static int pipe_handler_request(struct sock *sk, u8 id, u8 code, const void *data, int len) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *ph; struct sk_buff *skb; skb = pep_alloc_skb(sk, data, len, GFP_KERNEL); if (!skb) return -ENOMEM; ph = pnp_hdr(skb); ph->utid = id; /* whatever */ ph->message_id = id; ph->pipe_handle = pn->pipe_handle; ph->data[0] = code; return pn_skb_send(sk, skb, NULL); }

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static int pipe_handler_send_created_ind(struct sock *sk) { struct pep_sock *pn = pep_sk(sk); u8 data[4] = { PN_PIPE_SB_NEGOTIATED_FC, pep_sb_size(2), pn->tx_fc, pn->rx_fc, }; return pep_indicate(sk, PNS_PIPE_CREATED_IND, 1 /* sub-blocks */, data, 4, GFP_ATOMIC); }

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static int pep_accept_conn(struct sock *sk, struct sk_buff *skb) { static const u8 data[20] = { PAD, PAD, PAD, 2 /* sub-blocks */, PN_PIPE_SB_REQUIRED_FC_TX, pep_sb_size(5), 3, PAD, PN_MULTI_CREDIT_FLOW_CONTROL, PN_ONE_CREDIT_FLOW_CONTROL, PN_LEGACY_FLOW_CONTROL, PAD, PN_PIPE_SB_PREFERRED_FC_RX, pep_sb_size(5), 3, PAD, PN_MULTI_CREDIT_FLOW_CONTROL, PN_ONE_CREDIT_FLOW_CONTROL, PN_LEGACY_FLOW_CONTROL, PAD, }; might_sleep(); return pep_reply(sk, skb, PN_PIPE_NO_ERROR, data, sizeof(data), GFP_KERNEL); }

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static int pep_reject_conn(struct sock *sk, struct sk_buff *skb, u8 code, gfp_t priority) { static const u8 data[4] = { PAD, PAD, PAD, 0 /* sub-blocks */ }; WARN_ON(code == PN_PIPE_NO_ERROR); return pep_reply(sk, skb, code, data, sizeof(data), priority); }

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/* Control requests are not sent by the pipe service and have a specific * message format. */
static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code, gfp_t priority) { const struct pnpipehdr *oph = pnp_hdr(oskb); struct sk_buff *skb; struct pnpipehdr *ph; struct sockaddr_pn dst; u8 data[4] = { oph->data[0], /* PEP type */ code, /* error code, at an unusual offset */ PAD, PAD, }; skb = pep_alloc_skb(sk, data, 4, priority); if (!skb) return -ENOMEM; ph = pnp_hdr(skb); ph->utid = oph->utid; ph->message_id = PNS_PEP_CTRL_RESP; ph->pipe_handle = oph->pipe_handle; ph->data[0] = oph->data[1]; /* CTRL id */ pn_skb_get_src_sockaddr(oskb, &dst); return pn_skb_send(sk, skb, &dst); }

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static int pipe_snd_status(struct sock *sk, u8 type, u8 status, gfp_t priority) { u8 data[4] = { type, PAD, PAD, status }; return pep_indicate(sk, PNS_PEP_STATUS_IND, PN_PEP_TYPE_COMMON, data, 4, priority); }

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/* Send our RX flow control information to the sender. * Socket must be locked. */
static void pipe_grant_credits(struct sock *sk, gfp_t priority) { struct pep_sock *pn = pep_sk(sk); BUG_ON(sk->sk_state != TCP_ESTABLISHED); switch (pn->rx_fc) { case PN_LEGACY_FLOW_CONTROL: /* TODO */ break; case PN_ONE_CREDIT_FLOW_CONTROL: if (pipe_snd_status(sk, PN_PEP_IND_FLOW_CONTROL, PEP_IND_READY, priority) == 0) pn->rx_credits = 1; break; case PN_MULTI_CREDIT_FLOW_CONTROL: if ((pn->rx_credits + CREDITS_THR) > CREDITS_MAX) break; if (pipe_snd_status(sk, PN_PEP_IND_ID_MCFC_GRANT_CREDITS, CREDITS_MAX - pn->rx_credits, priority) == 0) pn->rx_credits = CREDITS_MAX; break; } }

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static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *hdr; int wake = 0; if (!pskb_may_pull(skb, sizeof(*hdr) + 4)) return -EINVAL; hdr = pnp_hdr(skb); if (hdr->data[0] != PN_PEP_TYPE_COMMON) { net_dbg_ratelimited("Phonet unknown PEP type: %u\n", (unsigned int)hdr->data[0]); return -EOPNOTSUPP; } switch (hdr->data[1]) { case PN_PEP_IND_FLOW_CONTROL: switch (pn->tx_fc) { case PN_LEGACY_FLOW_CONTROL: switch (hdr->data[4]) { case PEP_IND_BUSY: atomic_set(&pn->tx_credits, 0); break; case PEP_IND_READY: atomic_set(&pn->tx_credits, wake = 1); break; } break; case PN_ONE_CREDIT_FLOW_CONTROL: if (hdr->data[4] == PEP_IND_READY) atomic_set(&pn->tx_credits, wake = 1); break; } break; case PN_PEP_IND_ID_MCFC_GRANT_CREDITS: if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL) break; atomic_add(wake = hdr->data[4], &pn->tx_credits); break; default: net_dbg_ratelimited("Phonet unknown PEP indication: %u\n", (unsigned int)hdr->data[1]); return -EOPNOTSUPP; } if (wake) sk->sk_write_space(sk); return 0; }

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eric dumazeteric dumazet20.78%120.00%
Total256100.00%5100.00%


static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *hdr = pnp_hdr(skb); u8 n_sb = hdr->data[0]; pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL; __skb_pull(skb, sizeof(*hdr)); while (n_sb > 0) { u8 type, buf[2], len = sizeof(buf); u8 *data = pep_get_sb(skb, &type, &len, buf); if (data == NULL) return -EINVAL; switch (type) { case PN_PIPE_SB_NEGOTIATED_FC: if (len < 2 || (data[0] | data[1]) > 3) break; pn->tx_fc = data[0] & 3; pn->rx_fc = data[1] & 3; break; } n_sb--; } return 0; }

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/* Queue an skb to a connected sock. * Socket lock must be held. */
static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *hdr = pnp_hdr(skb); struct sk_buff_head *queue; int err = 0; BUG_ON(sk->sk_state == TCP_CLOSE_WAIT); switch (hdr->message_id) { case PNS_PEP_CONNECT_REQ: pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE, GFP_ATOMIC); break; case PNS_PEP_DISCONNECT_REQ: pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC); sk->sk_state = TCP_CLOSE_WAIT; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); break; case PNS_PEP_ENABLE_REQ: /* Wait for PNS_PIPE_(ENABLED|REDIRECTED)_IND */ pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC); break; case PNS_PEP_RESET_REQ: switch (hdr->state_after_reset) { case PN_PIPE_DISABLE: pn->init_enable = 0; break; case PN_PIPE_ENABLE: pn->init_enable = 1; break; default: /* not allowed to send an error here!? */ err = -EINVAL; goto out; } /* fall through */ case PNS_PEP_DISABLE_REQ: atomic_set(&pn->tx_credits, 0); pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC); break; case PNS_PEP_CTRL_REQ: if (skb_queue_len(&pn->ctrlreq_queue) >= PNPIPE_CTRLREQ_MAX) { atomic_inc(&sk->sk_drops); break; } __skb_pull(skb, 4); queue = &pn->ctrlreq_queue; goto queue; case PNS_PIPE_ALIGNED_DATA: __skb_pull(skb, 1); /* fall through */ case PNS_PIPE_DATA: __skb_pull(skb, 3); /* Pipe data header */ if (!pn_flow_safe(pn->rx_fc)) { err = sock_queue_rcv_skb(sk, skb); if (!err) return NET_RX_SUCCESS; err = -ENOBUFS; break; } if (pn->rx_credits == 0) { atomic_inc(&sk->sk_drops); err = -ENOBUFS; break; } pn->rx_credits--; queue = &sk->sk_receive_queue; goto queue; case PNS_PEP_STATUS_IND: pipe_rcv_status(sk, skb); break; case PNS_PIPE_REDIRECTED_IND: err = pipe_rcv_created(sk, skb); break; case PNS_PIPE_CREATED_IND: err = pipe_rcv_created(sk, skb); if (err) break; /* fall through */ case PNS_PIPE_RESET_IND: if (!pn->init_enable) break; /* fall through */ case PNS_PIPE_ENABLED_IND: if (!pn_flow_safe(pn->tx_fc)) { atomic_set(&pn->tx_credits, 1); sk->sk_write_space(sk); } if (sk->sk_state == TCP_ESTABLISHED) break; /* Nothing to do */ sk->sk_state = TCP_ESTABLISHED; pipe_grant_credits(sk, GFP_ATOMIC); break; case PNS_PIPE_DISABLED_IND: sk->sk_state = TCP_SYN_RECV; pn->rx_credits = 0; break; default: net_dbg_ratelimited("Phonet unknown PEP message: %u\n", hdr->message_id); err = -EINVAL; } out: kfree_skb(skb); return (err == -ENOBUFS) ? NET_RX_DROP : NET_RX_SUCCESS; queue: skb->dev = NULL; skb_set_owner_r(skb, sk); skb_queue_tail(queue, skb); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk); return NET_RX_SUCCESS; }

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Total552100.00%11100.00%

/* Destroy connected sock. */
static void pipe_destruct(struct sock *sk) { struct pep_sock *pn = pep_sk(sk); skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&pn->ctrlreq_queue); }

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static u8 pipe_negotiate_fc(const u8 *fcs, unsigned int n) { unsigned int i; u8 final_fc = PN_NO_FLOW_CONTROL; for (i = 0; i < n; i++) { u8 fc = fcs[i]; if (fc > final_fc && fc < PN_MAX_FLOW_CONTROL) final_fc = fc; } return final_fc; }

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static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *hdr; u8 n_sb; if (!pskb_pull(skb, sizeof(*hdr) + 4)) return -EINVAL; hdr = pnp_hdr(skb); if (hdr->error_code != PN_PIPE_NO_ERROR) return -ECONNREFUSED; /* Parse sub-blocks */ n_sb = hdr->data[4]; while (n_sb > 0) { u8 type, buf[6], len = sizeof(buf); const u8 *data = pep_get_sb(skb, &type, &len, buf); if (data == NULL) return -EINVAL; switch (type) { case PN_PIPE_SB_REQUIRED_FC_TX: if (len < 2 || len < data[0]) break; pn->tx_fc = pipe_negotiate_fc(data + 2, len - 2); break; case PN_PIPE_SB_PREFERRED_FC_RX: if (len < 2 || len < data[0]) break; pn->rx_fc = pipe_negotiate_fc(data + 2, len - 2); break; } n_sb--; } return pipe_handler_send_created_ind(sk); }

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Total215100.00%3100.00%


static int pep_enableresp_rcv(struct sock *sk, struct sk_buff *skb) { struct pnpipehdr *hdr = pnp_hdr(skb); if (hdr->error_code != PN_PIPE_NO_ERROR) return -ECONNREFUSED; return pep_indicate(sk, PNS_PIPE_ENABLED_IND, 0 /* sub-blocks */, NULL, 0, GFP_ATOMIC); }

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static void pipe_start_flow_control(struct sock *sk) { struct pep_sock *pn = pep_sk(sk); if (!pn_flow_safe(pn->tx_fc)) { atomic_set(&pn->tx_credits, 1); sk->sk_write_space(sk); } pipe_grant_credits(sk, GFP_ATOMIC); }

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/* Queue an skb to an actively connected sock. * Socket lock must be held. */
static int pipe_handler_do_rcv(struct sock *sk, struct sk_buff *skb) { struct pep_sock *pn = pep_sk(sk); struct pnpipehdr *hdr = pnp_hdr(skb); int err = NET_RX_SUCCESS; switch (hdr->message_id) { case PNS_PIPE_ALIGNED_DATA: __skb_pull(skb, 1); /* fall through */ case PNS_PIPE_DATA: __skb_pull(skb, 3); /* Pipe data header */ if (!pn_flow_safe(pn->rx_fc)) { err = sock_queue_rcv_skb(sk, skb); if (!err) return NET_RX_SUCCESS; err = NET_RX_DROP; break; } if (pn->rx_credits == 0) { atomic_inc(&sk->sk_drops); err = NET_RX_DROP; break; } pn->rx_credits--; skb->dev = NULL; skb_set_owner_r(skb, sk); skb_queue_tail(&sk->sk_receive_queue, skb); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk); return NET_RX_SUCCESS; case PNS_PEP_CONNECT_RESP: if (sk->sk_state != TCP_SYN_SENT) break; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); if (pep_connresp_rcv(sk, skb)) { sk->sk_state = TCP_CLOSE_WAIT; break; } if (pn->init_enable == PN_PIPE_DISABLE) sk->sk_state