From e89c2095815d82eaa9fb85eff42f8b65b67a59cf Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Thu, 25 Dec 2008 16:54:58 -0800 Subject: [PATCH] sctp: Bring SCTP_MAXSEG socket option into ietf API extension compliance Brings maxseg socket option set/get into line with the latest ietf socket extensions API draft, while maintaining backwards compatibility. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/sctp/socket.c | 130 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 107 insertions(+), 23 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index a2de585888d..0738843876a 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -2778,32 +2778,77 @@ static int sctp_setsockopt_mappedv4(struct sock *sk, char __user *optval, int op } /* - * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG) - * - * This socket option specifies the maximum size to put in any outgoing - * SCTP chunk. If a message is larger than this size it will be + * 8.1.16. Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG) + * This option will get or set the maximum size to put in any outgoing + * SCTP DATA chunk. If a message is larger than this size it will be * fragmented by SCTP into the specified size. Note that the underlying * SCTP implementation may fragment into smaller sized chunks when the * PMTU of the underlying association is smaller than the value set by - * the user. + * the user. The default value for this option is '0' which indicates + * the user is NOT limiting fragmentation and only the PMTU will effect + * SCTP's choice of DATA chunk size. Note also that values set larger + * than the maximum size of an IP datagram will effectively let SCTP + * control fragmentation (i.e. the same as setting this option to 0). + * + * The following structure is used to access and modify this parameter: + * + * struct sctp_assoc_value { + * sctp_assoc_t assoc_id; + * uint32_t assoc_value; + * }; + * + * assoc_id: This parameter is ignored for one-to-one style sockets. + * For one-to-many style sockets this parameter indicates which + * association the user is performing an action upon. Note that if + * this field's value is zero then the endpoints default value is + * changed (effecting future associations only). + * assoc_value: This parameter specifies the maximum size in bytes. */ static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, int optlen) { + struct sctp_assoc_value params; struct sctp_association *asoc; struct sctp_sock *sp = sctp_sk(sk); int val; - if (optlen < sizeof(int)) + if (optlen == sizeof(int)) { + printk(KERN_WARNING + "SCTP: Use of int in maxseg socket option deprecated\n"); + printk(KERN_WARNING + "SCTP: Use struct sctp_assoc_value instead\n"); + if (copy_from_user(&val, optval, optlen)) + return -EFAULT; + params.assoc_id = 0; + } else if (optlen == sizeof(struct sctp_assoc_value)) { + if (copy_from_user(¶ms, optval, optlen)) + return -EFAULT; + val = params.assoc_value; + } else return -EINVAL; - if (get_user(val, (int __user *)optval)) - return -EFAULT; + if ((val != 0) && ((val < 8) || (val > SCTP_MAX_CHUNK_LEN))) return -EINVAL; - sp->user_frag = val; - /* Update the frag_point of the existing associations. */ - list_for_each_entry(asoc, &(sp->ep->asocs), asocs) { - asoc->frag_point = sctp_frag_point(sp, asoc->pathmtu); + asoc = sctp_id2assoc(sk, params.assoc_id); + if (!asoc && params.assoc_id && sctp_style(sk, UDP)) + return -EINVAL; + + if (asoc) { + if (val == 0) { + val = asoc->pathmtu; + val -= sp->pf->af->net_header_len; + val -= sizeof(struct sctphdr) + + sizeof(struct sctp_data_chunk); + } + + asoc->frag_point = val; + } else { + sp->user_frag = val; + + /* Update the frag_point of the existing associations. */ + list_for_each_entry(asoc, &(sp->ep->asocs), asocs) { + asoc->frag_point = sctp_frag_point(sp, asoc->pathmtu); + } } return 0; @@ -5100,30 +5145,69 @@ static int sctp_getsockopt_context(struct sock *sk, int len, } /* - * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG) - * - * This socket option specifies the maximum size to put in any outgoing - * SCTP chunk. If a message is larger than this size it will be + * 8.1.16. Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG) + * This option will get or set the maximum size to put in any outgoing + * SCTP DATA chunk. If a message is larger than this size it will be * fragmented by SCTP into the specified size. Note that the underlying * SCTP implementation may fragment into smaller sized chunks when the * PMTU of the underlying association is smaller than the value set by - * the user. + * the user. The default value for this option is '0' which indicates + * the user is NOT limiting fragmentation and only the PMTU will effect + * SCTP's choice of DATA chunk size. Note also that values set larger + * than the maximum size of an IP datagram will effectively let SCTP + * control fragmentation (i.e. the same as setting this option to 0). + * + * The following structure is used to access and modify this parameter: + * + * struct sctp_assoc_value { + * sctp_assoc_t assoc_id; + * uint32_t assoc_value; + * }; + * + * assoc_id: This parameter is ignored for one-to-one style sockets. + * For one-to-many style sockets this parameter indicates which + * association the user is performing an action upon. Note that if + * this field's value is zero then the endpoints default value is + * changed (effecting future associations only). + * assoc_value: This parameter specifies the maximum size in bytes. */ static int sctp_getsockopt_maxseg(struct sock *sk, int len, char __user *optval, int __user *optlen) { - int val; + struct sctp_assoc_value params; + struct sctp_association *asoc; - if (len < sizeof(int)) + if (len == sizeof(int)) { + printk(KERN_WARNING + "SCTP: Use of int in maxseg socket option deprecated\n"); + printk(KERN_WARNING + "SCTP: Use struct sctp_assoc_value instead\n"); + params.assoc_id = 0; + } else if (len >= sizeof(struct sctp_assoc_value)) { + len = sizeof(struct sctp_assoc_value); + if (copy_from_user(¶ms, optval, sizeof(params))) + return -EFAULT; + } else return -EINVAL; - len = sizeof(int); + asoc = sctp_id2assoc(sk, params.assoc_id); + if (!asoc && params.assoc_id && sctp_style(sk, UDP)) + return -EINVAL; + + if (asoc) + params.assoc_value = asoc->frag_point; + else + params.assoc_value = sctp_sk(sk)->user_frag; - val = sctp_sk(sk)->user_frag; if (put_user(len, optlen)) return -EFAULT; - if (copy_to_user(optval, &val, len)) - return -EFAULT; + if (len == sizeof(int)) { + if (copy_to_user(optval, ¶ms.assoc_value, len)) + return -EFAULT; + } else { + if (copy_to_user(optval, ¶ms, len)) + return -EFAULT; + } return 0; } -- 2.20.1