Implement simple packet loss simulation

mmss/config.cpp

@@ -66,12 +66,44 @@ bool config_t::add_network(const char *name) {
 		return false;
 	}
 
-
-	networks.insert(std::make_pair(name, std::make_shared<network_t>(name)));
+	current_net = &networks.insert(std::make_pair(name, std::make_shared<network_t>(mmss, name, rand_seed++))).first->second;
 
 	return true;
 }
 
+bool config_t::set_packet_loss(float etx) {
+	if (etx < 1) {
+		mmss->logf(LOG_ERR, "config error: network `%s': ETX must be at least 1.0", (*current_net)->get_name().c_str());
+		return false;
+	}
+
+	(*current_net)->set_packet_loss(etx);
+
+	return true;
+}
+
+bool config_t::set_packet_loss(float etx_min, float etx_max, float period, float phase) {
+	if (etx_min < 1) {
+		mmss->logf(LOG_ERR, "config error: network `%s': ETX must be at least 1.0", (*current_net)->get_name().c_str());
+		return false;
+	}
+
+	if (etx_max < etx_min) {
+		mmss->logf(LOG_ERR, "config error: network `%s': max ETX smaller than min ETX", (*current_net)->get_name().c_str());
+		return false;
+	}
+
+	if (period <= 0) {
+		mmss->logf(LOG_ERR, "config error: network `%s': zero or negative period", (*current_net)->get_name().c_str());
+		return false;
+	}
+
+	(*current_net)->set_packet_loss(etx_min, etx_max, period, phase);
+
+	return true;
+}
+
+
 bool config_t::add_node(const char *name, const char *proto) {
 	if (nodes.find(name) != nodes.end()) {
 		mmss->logf(LOG_ERR, "config error: duplicate node `%s'", name);

mmss/config.hpp

@@ -44,6 +44,7 @@ private:
 	std::shared_ptr<const protocol_t> default_proto;
 	std::unordered_map<std::string, std::shared_ptr<const protocol_t>> protos;
 
+	const std::shared_ptr<network_t> *current_net;
 	std::unordered_map<std::string, std::shared_ptr<network_t>> networks;
 
 	const std::shared_ptr<node_t> *current_node;
@@ -57,7 +58,11 @@ public:
 	}
 
 	bool load_proto(const char *name, const char *module, bool def);
+
 	bool add_network(const char *name);
+	bool set_packet_loss(float etx);
+	bool set_packet_loss(float etx_min, float etx_max, float period, float phase);
+
 	bool add_node(const char *name, const char *proto);
 	bool add_iface(const char *name, const char *net, const gmrf_addr_t *addr);
 

mmss/config.l

@@ -57,7 +57,8 @@
 %}
 
 <INITIAL>{
-[0-9]+		{ UPDATE_LOCATION; yylval->num = atoi(yytext); BEGIN(NEEDSPACE); return TOK_INTEGER; }
+[0-9]+		{ UPDATE_LOCATION; yylval->num = std::atoi(yytext); BEGIN(NEEDSPACE); return TOK_INTEGER; }
+[0-9]*\.[0-9]+	{ UPDATE_LOCATION; yylval->fnum = float(std::atof(yytext)); BEGIN(NEEDSPACE); return TOK_FLOAT; }
 
 yes		{ TOKEN(TOK_YES); }
 no		{ TOKEN(TOK_NO); }
@@ -68,6 +69,13 @@ load		{ TOKEN(TOK_LOAD); }
 default		{ TOKEN(TOK_DEFAULT); }
 interface	{ TOKEN(TOK_INTERFACE); }
 address		{ TOKEN(TOK_ADDRESS); }
+etx		{ TOKEN(TOK_ETX); }
+const		{ TOKEN(TOK_CONST); }
+min		{ TOKEN(TOK_MIN); }
+max		{ TOKEN(TOK_MAX); }
+sine		{ TOKEN(TOK_SINE); }
+period		{ TOKEN(TOK_PERIOD); }
+phase		{ TOKEN(TOK_PHASE); }
 
 ([[:xdigit:]]{2}:){7}[[:xdigit:]]{2} {
 			UPDATE_LOCATION;
@@ -86,6 +94,13 @@ address		{ TOKEN(TOK_ADDRESS); }
 \r		;
 }
 
+<INITIAL,NEEDSPACE>{
+s		{ TOKEN(TOK_S); }
+m		{ TOKEN(TOK_M); }
+h		{ TOKEN(TOK_H); }
+days		{ TOKEN(TOK_DAYS); }
+}
+
 <NEEDSPACE>{
 [;:\{\}]	{ UPDATE_LOCATION; BEGIN(INITIAL); return yytext[0]; }
 

mmss/config.y

@@ -41,6 +41,7 @@
 
 %union {
 	int num;
+	float fnum;
 	bool boolean;
 	char *str;
 	gmrf_addr_t addr;
@@ -49,6 +50,7 @@
 }
 
 %token <num> TOK_INTEGER
+%token <fnum> TOK_FLOAT
 %token <str> TOK_STRING
 %token <addr> TOK_GMRF_ADDRESS
 
@@ -61,6 +63,18 @@
 %token TOK_DEFAULT
 %token TOK_INTERFACE
 %token TOK_ADDRESS
+%token TOK_ETX
+%token TOK_CONST
+%token TOK_MIN
+%token TOK_MAX
+%token TOK_SINE
+%token TOK_PERIOD
+%token TOK_PHASE
+
+%token TOK_S
+%token TOK_M
+%token TOK_H
+%token TOK_DAYS
 
 
 %code {
@@ -71,6 +85,8 @@
 %type <boolean> boolean
 %type <boolean> maybe_default
 %type <str> maybe_protocol
+%type <num> time
+%type <fnum> float
 
 %%
 
@@ -92,7 +108,27 @@ network:	TOK_STRING {
 		}
 	;
 
-network_config:
+network_config: network_config network_statement
+	|
+	;
+
+network_statement:
+		TOK_ETX network_etx ';'
+	;
+
+network_etx:
+		TOK_CONST float {
+			if (!conf->set_packet_loss($2))
+				YYERROR;
+		}
+	|	TOK_MIN float TOK_MAX float TOK_SINE TOK_PERIOD time {
+			if (!conf->set_packet_loss($2, $4, $7, 0))
+				YYERROR;
+		}
+	|	TOK_MIN float TOK_MAX float TOK_SINE TOK_PERIOD time TOK_PHASE time {
+			if (!conf->set_packet_loss($2, $4, $7, $9))
+				YYERROR;
+		}
 	;
 
 protocol:	TOK_STRING TOK_LOAD TOK_STRING maybe_default {
@@ -120,6 +156,10 @@ node_interface:	TOK_STRING TOK_NETWORK TOK_STRING TOK_ADDRESS TOK_GMRF_ADDRESS {
 		}
 	;
 
+float:		TOK_FLOAT	{ $$ = $1; }
+	|	TOK_INTEGER	{ $$ = $1; }
+	;
+
 boolean:	TOK_YES		{ $$ = true; }
 	|	TOK_NO		{ $$ = false; }
 	;
@@ -132,6 +172,13 @@ maybe_protocol:	TOK_PROTOCOL TOK_STRING	{ $$ = $2; }
 	|			{ $$ = nullptr; }
 	;
 
+time:		TOK_INTEGER TOK_DAYS { $$ = $1*86400; }
+	|	TOK_INTEGER TOK_H    { $$ = $1*3600; }
+	|	TOK_INTEGER TOK_M    { $$ = $1*60; }
+	|	TOK_INTEGER TOK_S    { $$ = $1; }
+	|	TOK_INTEGER          { $$ = $1; }
+	;
+
 %%
 
 void mmss_config_error(YYLTYPE *loc, const std::shared_ptr<config_t> &conf, const char *filename, const char *s) {

mmss/network.cpp

@@ -28,11 +28,33 @@
 #include "context.hpp"
 #include "node.hpp"
 
+#include <cmath>
+#include <cstdlib>
+
 
 namespace MMSS {
 
+float network_t::get_etx() const {
+	if (etx_min == etx_max)
+		return etx_min;
+
+	float val = float(std::sin(2*M_PI * (mmss->now()/1000.0 - phase)/period));
+	float diff = etx_max - etx_min;
+
+	mmss->logf(LOG_DEBUG, "ETX: %.3f", etx_min + diff * (val+1)/2);
+
+	return etx_min + diff * (val+1)/2;
+}
+
+bool network_t::drop_packet() {
+	int r = rand_r(&rand_seed);
+
+	return (r > (RAND_MAX/get_etx()));
+}
+
 void network_t::enqueue(const void *data, size_t len, const iface_t *src_iface, const std::shared_ptr<iface_t> &dest_iface) {
-	context_t *mmss = dest_iface->get_node()->get_context();
+	if (drop_packet())
+		return;
 
 	std::shared_ptr<packet_t> packet = std::make_shared<packet_t>(src_iface->get_address(), dest_iface, data, len);
 	mmss->queue_event(std::move(packet), mmss->now()+1);

mmss/network.hpp

@@ -36,20 +36,49 @@ namespace MMSS {
 
 class network_t : public nocopy_t {
 private:
+	context_t *mmss;
+
 	std::string name;
 	size_t mtu;
 
+	unsigned rand_seed;
+
+	// packet loss
+	float etx_min;
+	float etx_max;
+	float period;
+	float phase;
+
 	std::unordered_set<std::shared_ptr<iface_t>> interfaces;
 
+	float get_etx() const;
+
+	bool drop_packet();
 	void enqueue(const void *data, size_t len, const iface_t *src_iface, const std::shared_ptr<iface_t> &dest_iface);
 
 public:
-	network_t(const std::string &name0) : name(name0), mtu(1500) {}
+	network_t(context_t *mmss0, const std::string &name0, unsigned rand_seed0)
+		: mmss(mmss0), name(name0), mtu(1500), rand_seed(rand_seed0), etx_min(1), etx_max(1) {}
+
+	void set_packet_loss(float etx) {
+		etx_min = etx_max = etx;
+	}
+
+	void set_packet_loss(float etx_min0, float etx_max0, float period0, float phase0) {
+		etx_min = etx_min0;
+		etx_max = etx_max0;
+		period = period0;
+		phase = phase0;
+	}
 
 	void add_iface(const std::shared_ptr<iface_t> &iface) {
 		interfaces.insert(iface);
 	}
 
+	context_t* get_context() const {
+		return mmss;
+	}
+
 	const std::string& get_name() const {
 		return name;
 	}

mmss/node.hpp

@@ -38,9 +38,6 @@ namespace MMSS {
 
 class node_t : public ::gmrf, public std::enable_shared_from_this<node_t>, public nocopy_t {
 private:
-	node_t(node_t const&) = delete;
-	node_t& operator=(node_t const&) = delete;
-
 	context_t *mmss;
 
 	std::string name;