diff options
| -rw-r--r-- | src/modules/m_ident.cpp | 126 |
1 files changed, 108 insertions, 18 deletions
diff --git a/src/modules/m_ident.cpp b/src/modules/m_ident.cpp index 705b0d16d..fd76e87be 100644 --- a/src/modules/m_ident.cpp +++ b/src/modules/m_ident.cpp @@ -18,24 +18,78 @@ /* $ModDesc: Provides support for RFC1413 ident lookups */ +/* -------------------------------------------------------------- + * Note that this is the third incarnation of m_ident. The first + * two attempts were pretty crashy, mainly due to the fact we tried + * to use InspSocket/BufferedSocket to make them work. This class + * is ok for more heavyweight tasks, it does a lot of things behind + * the scenes that are not good for ident sockets and it has a huge + * memory footprint! + * + * To fix all the issues that we had in the old ident modules (many + * nasty race conditions that would cause segfaults etc) we have + * rewritten this module to use a simplified socket object based + * directly off EventHandler. As EventHandler only has low level + * readability, writeability and error events tied directly to the + * socket engine, this makes our lives easier as nothing happens to + * our ident lookup class that is outside of this module, or out- + * side of the control of the class. There are no timers, internal + * events, or such, which will cause the socket to be deleted, + * queued for deletion, etc. In fact, theres not even any queueing! + * + * Using this framework we have a much more stable module. + * + * A few things to note: + * + * O The only place that may *delete* an active or inactive + * ident socket is OnUserDisconnect in the module class. + * Because this is out of scope of the socket class there is + * no possibility that the socket may ever try to delete + * itself. + * + * O Closure of the ident socket with the Close() method will + * not cause removal of the socket from memory or detatchment + * from its 'parent' User class. It will only flag it as an + * inactive socket in the socket engine. + * + * O Timeouts are handled in OnCheckReaady at the same time as + * checking if the ident socket has a result. This is done + * by checking if the age the of the class (its instantiation + * time) plus the timeout value is greater than the current time. + * + * O The ident socket is able to but should not modify its + * 'parent' user directly. Instead the ident socket class sets + * a completion flag and during the next call to OnCheckReady, + * the completion flag will be checked and any result copied to + * that user's class. This again ensures a single point of socket + * deletion for safer, neater code. + * + * O The code in the constructor of the ident socket is taken from + * BufferedSocket but majorly thinned down. It works for both + * IPv4 and IPv6. + * + * O In the event that the ident socket throws a ModuleException, + * nothing is done. This is counted as total and complete + * failure to create a connection. + * -------------------------------------------------------------- + */ + class IdentRequestSocket : public EventHandler { private: - User *user; - InspIRCd* ServerInstance; - bool done; - std::string result; + User *user; /* User we are attached to */ + InspIRCd* ServerInstance; /* Server instance */ + bool done; /* True if lookup is finished */ + std::string result; /* Holds the ident string if done */ public: IdentRequestSocket(InspIRCd *Server, User* u, const std::string &bindip) : user(u), ServerInstance(Server), result(u->ident) { - /* connect here on instantiation, throw on immediate failure */ - socklen_t size = 0; - #ifdef IPV6 + /* Does this look like a v6 ip address? */ bool v6 = false; if ((bindip.empty()) || bindip.find(':') != std::string::npos) v6 = true; @@ -49,10 +103,12 @@ class IdentRequestSocket : public EventHandler if (GetFd() == -1) throw ModuleException("Could not create socket"); + /* We allocate two of these because sizeof(sockaddr_in6) > sizeof(sockaddr_in) */ sockaddr* s = new sockaddr[2]; sockaddr* addr = new sockaddr[2]; #ifdef IPV6 + /* Horrid icky nasty ugly berkely socket crap. */ if (v6) { in6_addr addy; @@ -87,6 +143,7 @@ class IdentRequestSocket : public EventHandler } } + /* Attempt to bind (ident requests must come from the ip the query is referring to */ if (ServerInstance->SE->Bind(GetFd(), s, size) < 0) { this->Close(); @@ -97,6 +154,7 @@ class IdentRequestSocket : public EventHandler delete[] s; ServerInstance->SE->NonBlocking(GetFd()); + /* Attempt connection (nonblocking) */ if (ServerInstance->SE->Connect(this, (sockaddr*)addr, size) == -1 && errno != EINPROGRESS) { this->Close(); @@ -106,12 +164,16 @@ class IdentRequestSocket : public EventHandler delete[] addr; + /* Add fd to socket engine */ if (!ServerInstance->SE->AddFd(this)) { this->Close(); throw ModuleException("out of fds"); } + /* Important: We set WantWrite immediately after connect() + * because a successful connection will trigger a writability event + */ ServerInstance->SE->WantWrite(this); } @@ -122,7 +184,6 @@ class IdentRequestSocket : public EventHandler /* Both sockaddr_in and sockaddr_in6 can be safely casted to sockaddr, especially since the * only members we use are in a part of the struct that should always be identical (at the * byte level). */ - #ifndef IPV6 sockaddr_in laddr, raddr; #else @@ -140,12 +201,16 @@ class IdentRequestSocket : public EventHandler char req[32]; + /* Build request in the form 'localport,remoteport\r\n' */ #ifndef IPV6 int req_size = snprintf(req, sizeof(req), "%d,%d\r\n", ntohs(raddr.sin_port), ntohs(laddr.sin_port)); #else int req_size = snprintf(req, sizeof(req), "%d,%d\r\n", ntohs(raddr.sin6_port), ntohs(laddr.sin6_port)); #endif + /* Send failed if we didnt write the whole ident request -- + * might as well give up if this happens! + */ if (ServerInstance->SE->Send(this, req, req_size, 0) < req_size) done = true; } @@ -165,6 +230,9 @@ class IdentRequestSocket : public EventHandler case EVENT_ERROR: /* fd error event, ohshi- */ ServerInstance->Log(DEBUG,"EVENT_ERROR"); + /* We *must* Close() here immediately or we get a + * huge storm of EVENT_ERROR events! + */ Close(); done = true; break; @@ -173,6 +241,9 @@ class IdentRequestSocket : public EventHandler void Close() { + /* Remove ident socket from engine, and close it, but dont detatch it + * from its parent user class, or attempt to delete its memory. + */ if (GetFd() > -1) { ServerInstance->Log(DEBUG,"Close ident socket %d", GetFd()); @@ -188,6 +259,9 @@ class IdentRequestSocket : public EventHandler return done; } + /* Note: if the lookup succeeded, will contain 'ident', otherwise + * will contain '~ident'. Use *GetResult() to determine lookup success. + */ const char* GetResult() { return result.c_str(); @@ -197,13 +271,15 @@ class IdentRequestSocket : public EventHandler { ServerInstance->Log(DEBUG,"ReadResponse()"); - // We don't really need to buffer for incomplete replies here, since IDENT replies are - // extremely short - there is *no* sane reason it'd be in more than one packet - + /* We don't really need to buffer for incomplete replies here, since IDENT replies are + * extremely short - there is *no* sane reason it'd be in more than one packet + */ char ibuf[MAXBUF]; int recvresult = ServerInstance->SE->Recv(this, ibuf, MAXBUF-1, 0); - /* Cant possibly be a valid response shorter than 3 chars */ + /* Cant possibly be a valid response shorter than 3 chars, + * because the shortest possible response would look like: '1,1' + */ if (recvresult < 3) { done = true; @@ -214,20 +290,20 @@ class IdentRequestSocket : public EventHandler std::string token; for (int i = 0; sep.GetToken(token); i++) { - // We only really care about the 4th portion + /* We only really care about the 4th portion */ if (i < 3) continue; char ident[IDENTMAX + 2]; - // Truncate the ident at any characters we don't like, skip leading spaces + /* Truncate the ident at any characters we don't like, skip leading spaces */ int k = 0; for (const char *j = token.c_str(); *j && (k < IDENTMAX + 1); j++) { if (*j == ' ') continue; - // Rules taken from InspIRCd::IsIdent + /* Rules taken from InspIRCd::IsIdent */ if (((*j >= 'A') && (*j <= '}')) || ((*j >= '0') && (*j <= '9')) || (*j == '-') || (*j == '.')) { ident[k++] = *j; @@ -239,7 +315,7 @@ class IdentRequestSocket : public EventHandler ident[k] = '\0'; - // Redundant check with IsIdent, in case that changes and this doesn't (paranoia!) + /* Re-check with IsIdent, in case that changes and this doesn't (paranoia!) */ if (*ident && ServerInstance->IsIdent(ident)) { result = ident; @@ -249,6 +325,9 @@ class IdentRequestSocket : public EventHandler break; } + /* Close (but dont delete from memory) our socket + * and flag as done + */ Close(); done = true; return; @@ -291,7 +370,7 @@ class ModuleIdent : public Module * should be preceded by a ~. The field is actually IDENTMAX+2 characters wide. */ memmove(user->ident + 1, user->ident, IDENTMAX); user->ident[0] = '~'; - // Ensure that it is null terminated + /* Ensure that it is null terminated */ user->ident[IDENTMAX + 1] = '\0'; user->WriteServ("NOTICE Auth :*** Looking up your ident..."); @@ -332,6 +411,10 @@ class ModuleIdent : public Module return 0; } + /* This triggers pretty regularly, we can use it in preference to + * creating a Timer object and especially better than creating a + * Timer per ident lookup! + */ virtual bool OnCheckReady(User *user) { ServerInstance->Log(DEBUG,"OnCheckReady %s", user->nick); @@ -346,11 +429,15 @@ class ModuleIdent : public Module ServerInstance->Log(DEBUG, "Has ident_socket"); + /* Check for timeout of the socket */ if (isock->age + RequestTimeout > ServerInstance->Time() && !isock->HasResult()) { /* Ident timeout */ user->WriteServ("NOTICE Auth :*** Ident request timed out."); ServerInstance->Log(DEBUG, "Timeout"); + /* The user isnt actually disconnecting, + * we call this to clean up the user + */ OnUserDisconnect(user); return true; } @@ -364,13 +451,16 @@ class ModuleIdent : public Module ServerInstance->Log(DEBUG, "Yay, result!"); - /* wooo, got a result! */ + /* wooo, got a result (it will be good, or bad) */ if (*(isock->GetResult()) != '~') user->WriteServ("NOTICE Auth :*** Found your ident, '%s'", isock->GetResult()); else user->WriteServ("NOTICE Auth :*** Could not find your ident, using %s instead.", isock->GetResult()); + /* Copy the ident string to the user */ strlcpy(user->ident, isock->GetResult(), IDENTMAX+1); + + /* The user isnt actually disconnecting, we call this to clean up the user */ OnUserDisconnect(user); return true; } |