[RFC 1/2] net: net_up, net_down

Ramon Fried rfried.dev at gmail.com
Wed May 5 04:02:21 CEST 2021


On Mon, May 3, 2021 at 2:55 PM Ian Ray <ian.ray at ge.com> wrote:
>
> Calls made to eth_halt() by network operations (ping, nfs, tftp, etc.)
> break netconsole if it is already running.
>
> * Maintain the network up / down state based on a reference count,
>   using new APIs net_up() and net_down().
>
> Note that when network is brought up by netconsole client, then network
> will remain up until reboot (because there is no way to stop netconsole
> itself).
>
> * Remove net_loop_last_protocol, eth_is_on_demand_init(), and
>   eth_set_last_protocol().  This functionality is replaced by
>   net_up() / net_down().
>
> * Replace usage of eth_init(), eth_halt() with net_up() and
>   net_down() in net.c, ping.c, tftp.c, and netconsole.c.
>
> Signed-off-by: Ian Ray <ian.ray at ge.com>
> ---
>  drivers/net/netconsole.c | 26 +++--------------
>  include/net.h            | 23 ++-------------
>  net/net.c                | 75 +++++++++++++++++++++++++++++++++---------------
>  net/ping.c               |  1 -
>  net/tftp.c               |  4 ---
>  net/wol.c                |  1 -
>  6 files changed, 59 insertions(+), 71 deletions(-)
>
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index f1d0630..b6d2e22 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -27,11 +27,6 @@ static short nc_out_port; /* target output port */
>  static short nc_in_port; /* source input port */
>  static const char *output_packet; /* used by first send udp */
>  static int output_packet_len;
> -/*
> - * Start with a default last protocol.
> - * We are only interested in NETCONS or not.
> - */
> -enum proto_t net_loop_last_protocol = BOOTP;
>
>  static void nc_wait_arp_handler(uchar *pkt, unsigned dest,
>                                  struct in_addr sip, unsigned src,
> @@ -177,7 +172,6 @@ static void nc_send_packet(const char *buf, int len)
>  #else
>         struct eth_device *eth;
>  #endif
> -       int inited = 0;
>         uchar *pkt;
>         uchar *ether;
>         struct in_addr ip;
> @@ -200,29 +194,17 @@ static void nc_send_packet(const char *buf, int len)
>                 return;
>         }
>
> -       if (!eth_is_active(eth)) {
> -               if (eth_is_on_demand_init()) {
> -                       if (eth_init() < 0)
> -                               return;
> -                       eth_set_last_protocol(NETCONS);
> -               } else {
> -                       eth_init_state_only();
> -               }
> -
> -               inited = 1;
> +       if (net_up(NETCONS) < 0) {
> +               return;
>         }
> +
>         pkt = (uchar *)net_tx_packet + net_eth_hdr_size() + IP_UDP_HDR_SIZE;
>         memcpy(pkt, buf, len);
>         ether = nc_ether;
>         ip = nc_ip;
>         net_send_udp_packet(ether, ip, nc_out_port, nc_in_port, len);
>
> -       if (inited) {
> -               if (eth_is_on_demand_init())
> -                       eth_halt();
> -               else
> -                       eth_halt_state_only();
> -       }
> +       net_down();
>  }
>
>  static int nc_stdio_start(struct stdio_dev *dev)
> diff --git a/include/net.h b/include/net.h
> index 1bf9867..cc6be60 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -599,6 +599,9 @@ int net_loop(enum proto_t);
>  /* Load failed.         Start again. */
>  int net_start_again(void);
>
> +int net_up(enum proto_t protocol);
> +int net_down(void);
> +
>  /* Get size of the ethernet header when we send */
>  int net_eth_hdr_size(void);
>
> @@ -706,26 +709,6 @@ int nc_input_packet(uchar *pkt, struct in_addr src_ip, unsigned dest_port,
>         unsigned src_port, unsigned len);
>  #endif
>
> -static __always_inline int eth_is_on_demand_init(void)
> -{
> -#if defined(CONFIG_NETCONSOLE) && !defined(CONFIG_SPL_BUILD)
> -       extern enum proto_t net_loop_last_protocol;
> -
> -       return net_loop_last_protocol != NETCONS;
> -#else
> -       return 1;
> -#endif
> -}
> -
> -static inline void eth_set_last_protocol(int protocol)
> -{
> -#if defined(CONFIG_NETCONSOLE) && !defined(CONFIG_SPL_BUILD)
> -       extern enum proto_t net_loop_last_protocol;
> -
> -       net_loop_last_protocol = protocol;
> -#endif
> -}
> -
>  /*
>   * Check if autoload is enabled. If so, use either NFS or TFTP to download
>   * the boot file.
> diff --git a/net/net.c b/net/net.c
> index 28d9eeb..45d4f19 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -404,6 +404,51 @@ void net_init(void)
>   *     Main network processing loop.
>   */
>
> +static int up_ref;
> +static bool up;
> +static bool keep_up;
> +
> +/// Bring net up/active if needed.
> +int net_up(enum proto_t protocol)
> +{
> +       int ret;
> +       if (!up) {
> +               eth_halt();
> +               eth_set_current();
> +               ret = eth_init();
> +               if (ret < 0) {
> +                       debug_cond(DEBUG_INT_STATE, "net_up failed\n");
> +                       eth_halt();
> +                       return ret;
> +               }
> +               up = true;
> +       } else if (up_ref == 0) {
> +               eth_init_state_only();
> +       }
> +       up_ref++;
> +       if (protocol == NETCONS) {
> +               keep_up = true;
> +       }
> +       return 0;
> +}
> +
> +/// Set net inactive if no clients remain.
> +int net_down(void)
> +{
> +       if (up_ref > 0) {
> +               up_ref--;
> +               if (up_ref == 0) {
> +                       if (keep_up) {
> +                               eth_halt_state_only();
> +                       } else {
> +                               up = false;
> +                               eth_halt();
> +                       }
> +               }
> +       }
> +       return 0;
> +}
> +
>  int net_loop(enum proto_t protocol)
>  {
>         int ret = -EINVAL;
> @@ -420,16 +465,9 @@ int net_loop(enum proto_t protocol)
>
>         bootstage_mark_name(BOOTSTAGE_ID_ETH_START, "eth_start");
>         net_init();
> -       if (eth_is_on_demand_init() || protocol != NETCONS) {
> -               eth_halt();
> -               eth_set_current();
> -               ret = eth_init();
> -               if (ret < 0) {
> -                       eth_halt();
> -                       return ret;
> -               }
> -       } else {
> -               eth_init_state_only();
> +       ret = net_up(protocol);
> +       if (ret < 0) {
> +               return ret;
>         }
>  restart:
>  #ifdef CONFIG_USB_KEYBOARD
> @@ -448,7 +486,7 @@ restart:
>         switch (net_check_prereq(protocol)) {
>         case 1:
>                 /* network not configured */
> -               eth_halt();
> +               net_down();
>                 net_set_state(prev_net_state);
>                 return -ENODEV;
>
> @@ -589,9 +627,7 @@ restart:
>                         net_arp_wait_packet_ip.s_addr = 0;
>
>                         net_cleanup_loop();
> -                       eth_halt();
> -                       /* Invalidate the last protocol */
> -                       eth_set_last_protocol(BOOTP);
> +                       net_down();
>
>                         puts("\nAbort\n");
>                         /* include a debug print as well incase the debug
> @@ -647,12 +683,7 @@ restart:
>                                 env_set_hex("filesize", net_boot_file_size);
>                                 env_set_hex("fileaddr", image_load_addr);
>                         }
> -                       if (protocol != NETCONS)
> -                               eth_halt();
> -                       else
> -                               eth_halt_state_only();
> -
> -                       eth_set_last_protocol(protocol);
> +                       net_down();
>
>                         ret = net_boot_file_size;
>                         debug_cond(DEBUG_INT_STATE, "--- net_loop Success!\n");
> @@ -660,8 +691,7 @@ restart:
>
>                 case NETLOOP_FAIL:
>                         net_cleanup_loop();
> -                       /* Invalidate the last protocol */
> -                       eth_set_last_protocol(BOOTP);
> +                       net_down();
>                         debug_cond(DEBUG_INT_STATE, "--- net_loop Fail!\n");
>                         ret = -ENONET;
>                         goto done;
> @@ -719,7 +749,6 @@ int net_start_again(void)
>         }
>
>         if ((!retry_forever) && (net_try_count > retrycnt)) {
> -               eth_halt();
>                 net_set_state(NETLOOP_FAIL);
>                 /*
>                  * We don't provide a way for the protocol to return an error,
> diff --git a/net/ping.c b/net/ping.c
> index 0e33660..2c92806 100644
> --- a/net/ping.c
> +++ b/net/ping.c
> @@ -64,7 +64,6 @@ static int ping_send(void)
>
>  static void ping_timeout_handler(void)
>  {
> -       eth_halt();
>         net_set_state(NETLOOP_FAIL);    /* we did not get the reply */
>  }
>
> diff --git a/net/tftp.c b/net/tftp.c
> index 84e970b..dcc387b 100644
> --- a/net/tftp.c
> +++ b/net/tftp.c
> @@ -652,7 +652,6 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
>                 net_set_timeout_handler(timeout_ms, tftp_timeout_handler);
>
>                 if (store_block(tftp_cur_block - 1, pkt + 2, len)) {
> -                       eth_halt();
>                         net_set_state(NETLOOP_FAIL);
>                         break;
>                 }
> @@ -680,7 +679,6 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
>                 case TFTP_ERR_FILE_NOT_FOUND:
>                 case TFTP_ERR_ACCESS_DENIED:
>                         puts("Not retrying...\n");
> -                       eth_halt();
>                         net_set_state(NETLOOP_FAIL);
>                         break;
>                 case TFTP_ERR_UNDEFINED:
> @@ -829,7 +827,6 @@ void tftp_start(enum proto_t protocol)
>  #endif
>         {
>                 if (tftp_init_load_addr()) {
> -                       eth_halt();
>                         net_set_state(NETLOOP_FAIL);
>                         puts("\nTFTP error: ");
>                         puts("trying to overwrite reserved memory...\n");
> @@ -885,7 +882,6 @@ void tftp_start_server(void)
>         tftp_filename[0] = 0;
>
>         if (tftp_init_load_addr()) {
> -               eth_halt();
>                 net_set_state(NETLOOP_FAIL);
>                 puts("\nTFTP error: trying to overwrite reserved memory...\n");
>                 return;
> diff --git a/net/wol.c b/net/wol.c
> index 0a62566..cd4e67e 100644
> --- a/net/wol.c
> +++ b/net/wol.c
> @@ -85,7 +85,6 @@ void wol_set_timeout(ulong timeout)
>
>  static void wol_timeout_handler(void)
>  {
> -       eth_halt();
>         net_set_state(NETLOOP_FAIL);
>  }
>
> --
> 2.10.1
>
I like the idea, I think that network protocols should call net_down()
when they're done, however I'm not sure we need reference count.
net_down() can be a wrapper around eth_halt(), We can just check if
netconsole is running and call it eth_halt() only if its' not.


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