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shell: telnet: Fix handling of multiple commands in a single packet

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In case multiple commands were sent in a single packet, only the first
one was processed. Fix this by processing them in a loop.

As the subnegotiation command have variable length, and we currently
don't have any support for subnegotiation, stop processing packet when
such a command occurs.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2021-11-05 16:39:13 +01:00 • committed by Christopher Friedt
commit c932354694
1 changed files with 31 additions and 5 deletions
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36
subsys/shell/backends/shell_telnet.c
View file

@ -31,6 +31,7 @@ struct shell_telnet *sh_telnet;
#define TELNET_TIMEOUT CONFIG_SHELL_TELNET_SEND_TIMEOUT #define TELNET_TIMEOUT CONFIG_SHELL_TELNET_SEND_TIMEOUT
#define TELNET_MIN_COMMAND_LEN 2 #define TELNET_MIN_COMMAND_LEN 2
#define TELNET_WILL_DO_COMMAND_LEN 3
/* Basic TELNET implmentation. */ /* Basic TELNET implmentation. */
@ -157,7 +158,7 @@ static void telnet_send_prematurely(struct k_work *work)
(void)telnet_send(); (void)telnet_send();
} }
static inline bool telnet_handle_command(struct net_pkt *pkt) static inline int telnet_handle_command(struct net_pkt *pkt)
{ {
/* Commands are two or three bytes. */ /* Commands are two or three bytes. */
NET_PKT_DATA_ACCESS_CONTIGUOUS_DEFINE(cmd_access, uint16_t); NET_PKT_DATA_ACCESS_CONTIGUOUS_DEFINE(cmd_access, uint16_t);
@ -166,7 +167,7 @@ static inline bool telnet_handle_command(struct net_pkt *pkt)
cmd = (struct telnet_simple_command *)net_pkt_get_data(pkt, cmd = (struct telnet_simple_command *)net_pkt_get_data(pkt,
&cmd_access); &cmd_access);
if (!cmd || cmd->iac != NVT_CMD_IAC) { if (!cmd || cmd->iac != NVT_CMD_IAC) {
return false; return 0;
} }
if (IS_ENABLED(CONFIG_SHELL_TELNET_SUPPORT_COMMAND)) { if (IS_ENABLED(CONFIG_SHELL_TELNET_SUPPORT_COMMAND)) {
@ -174,7 +175,17 @@ static inline bool telnet_handle_command(struct net_pkt *pkt)
telnet_reply_command(cmd); telnet_reply_command(cmd);
} }
return true; if (cmd->op == NVT_CMD_SB) {
/* TODO Add subnegotiation support. */
return -EOPNOTSUPP;
}
if (cmd->op == NVT_CMD_WILL || cmd->op == NVT_CMD_WONT ||
cmd->op == NVT_CMD_DO || cmd->op == NVT_CMD_DONT) {
return TELNET_WILL_DO_COMMAND_LEN;
}
return TELNET_MIN_COMMAND_LEN;
} }
static void telnet_recv(struct net_context *client, static void telnet_recv(struct net_context *client,
@ -185,6 +196,7 @@ static void telnet_recv(struct net_context *client,
void *user_data) void *user_data)
{ {
size_t len; size_t len;
int ret;
if (!pkt || status) { if (!pkt || status) {
telnet_end_client_connection(); telnet_end_client_connection();
@ -197,11 +209,25 @@ static void telnet_recv(struct net_context *client,
len = net_pkt_remaining_data(pkt); len = net_pkt_remaining_data(pkt);
if (len >= TELNET_MIN_COMMAND_LEN) { while (len >= TELNET_MIN_COMMAND_LEN) {
if (telnet_handle_command(pkt)) { ret = telnet_handle_command(pkt);
if (ret > 0) {
LOG_DBG("Handled command"); LOG_DBG("Handled command");
ret = net_pkt_skip(pkt, ret);
if (ret < 0) {
goto unref; goto unref;
} }
} else if (ret < 0) {
goto unref;
} else {
break;
}
len = net_pkt_remaining_data(pkt);
}
if (len == 0) {
goto unref;
} }
/* Fifo add */ /* Fifo add */